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  When I was a child, several decades ago, A.E. van Vogt was one of my favorite writers, on the same podium with Clarke, Asimov, Bradbury. Later, I was intrigued of how people never seemed to remember him, while praising loudly the others. So I got hold of whatever I could find written by him and started reminiscing.

  The Voyage of the Space Beagle is more of a short stories collection than a novel, even if it has the same characters spacing out on the same ship. It contains four stories:

  • Black Destroyer - a large cat-like alien tries to get the better of the crew
  • War of Nerves - an alien civilization makes contact telepathically, with unexpected results 
  • Discord in Scarlet - a red alien tries to get the better of the crew
  • M33 in Andromeda - a galactic sized alien tries to get the better of the crew
  • there are also some connective tissue paragraphs detailing a power struggle in the crew itself

  I know why I liked him when I was a kid. The people are all science and knowledge and decisiveness. They are impressive and sure minded and solve every dire situation with their power of their cunning. They also casually discuss and sometimes enact acts of genocide "on principle alone" because some aliens are too ugly, dangerous or of a different morality. It's an all male crew, chemically castrated like in the military, with not the slightest thought women could contribute in any way. They fly between galaxies with the strong sense of their own intellectual and (if proven wrong) moral superiority. The author puts out there the idea that the universe is several million years old and it cyclically explodes to create another one. The distance between stars and galaxies, as well as their number are ridiculously underestimated. Other knowledge we now take for granted is absent completely from the book.

  So it's a strange combination of strong people and ideas that look and feel ridiculous, insensitive, uneducated and even psychotic. The main reason is that the stories were not written at time of publication, but much earlier, sometimes in the '30s and then the author was constantly fixing them and mashing them together in fix-up novels. The scientific and social change in these 100 years is shocking. Hell, I was gleefully enjoying this 40 years ago! It has the effect of making me see our modern behavior through different eyes. We are as sure now as we were then that we are in the right and that we are a pinnacle of something and everything other is weird and to be changed or avoided. What will we think of present selves a century from now? How pathetic are the five minute dramas that occupy our awareness today.

  Think of this book as a precursor of Star Trek: valiant humans exploring the universe. Only they are as far from Kirk as he was from Picard. Quite intriguing an experience which I recommend.

  Van Vogt died in 2000, but his last short story was written in 1976. He was never considered a great writer even in his own time, despite my own childish preferences, yet he made an impact. I probably am going to read something by him again, maybe not immediately. 

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  At the end of Children of Ruin I was bemoaning the fact that Adrian Tchaikovsky moved things too far, too fast, and I was happy to see things go down a notch in the beginning of Children of Memory. Alas, it was all a scam, like those Star Trek episodes when nothing makes sense for the entire show only to get explained by a Deus ex Machina and a bunch of McGuffins at the end, but most of it happens in today's Earth or on some farm or Western setting.

  Where could the author have gone from a multi species confederation of faster than light travelers, capable of eternally sleeping during voyages anyway and, barring that, construct any body and transferring any kind of knowledge back and forth? Just like Stargate (most notably) which started with stranded humans at the mercy of all powerful aliens and ended up defeating gods and travelling between galaxies, the only way was back or some kind of lateral jump, like making episodic books that need not connect except through a common literary universe. I really hoped that would be the case.

  And I feel even worse because, while I hated most of the book, with its Memento-ish rehashings of the same events and with the author himself explaining obvious things over and over again, at the end of Children of Memory was a glimpse of the philosophical underpinnings of the story, and I liked those. Unfortunately those are just at the very end, making the rest of the book mostly pointless.

  Bottom line: I couldn't wait for the book to end fast enough, just to get to understand what was going on, because even if I had an inkling of that, I needed confirmation. And the ending was both philosophically satisfying and invalidating the entire beginning and middle of the the story. So to me it feels like a bad elevator episode of the series, like Tchaikovsky had one more book to write to make this a trilogy and, like me, couldn't wait to get it over with already. 

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  Children of Time was split into two stories, one rich with characterization, focused on individual people, and another that felt a little bit like a nature documentary, but was pretty good, too. The science was stretched a bit, but in the end you get a subtle exploration of humanity via another species. Children of Ruin is the equivalent of explosion porn for action movies, though: more, bigger, louder, thus drowning out the parts that came close to what I liked in the first book.

  Adrian Tchaikovsky starts with another pair of obsessive scientists, but there is less focus on their actual personalities and struggles. They become the cause and catalyst of what he really wanted to write about: a civilization of octopuses and a complete new alien species - which of course also reaches sentience. Strangely enough, these take a lot of the book without - to me - providing any insight into our own species or telling me anything really interesting and new about cephalopods or making me feel a lot about any of the characters. In a sentence: this book is less careful, larger but coarser, faster but less inspiring.

  This doesn't mean I didn't like it. The story captivated me and I wanted to know where it goes and how it ends, so I read it really fast. Yet the ending left me a bit disappointed, as I understood that the pyrotechnics ended and the story stands in ruin. Children of Memory seems to go back to the roots a little from the little I've read already, I hope it stays more true to the original concept.

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Saturn's Children feels like a book that started as something and turned out to be something else in the middle of it. Charles Stross writes something that seems very fashionable this days: a novel from the point of view of a robot. And not just any robot, but a humanoid female sex robot in a world devoid of humans with which to have sex with. Add some solar system travel, spy thriller mechanics, the occasional sexy comedy, philosophical musings about the meaning of life and identity, even what some people might consider light horror and you get this story.

  Even if I enjoyed it, the book is a mess. The style changes, the metaphors change from something from this decade to something that would only make sense in the far future populated exclusively by robots and back again. The mood changes, the motivation of the characters change. You can't even tell who is who anymore because of the multiple "soul chip" identity swaps. It is all written as a letter, but you can't tell who the letter is addressed to, since it also explains to us stuff that should be obvious to a robot.

  I found the premise of humanity simply fading away into extinction, no war, no plague, no asteroid, just people too distracted to have sex with other people, quite satisfying. I know that Futurama did it too, but it makes so much sense as a solution to the Fermi paradox. The basic idea of the book (once it crystalized into one) was intriguing, but you have to read half a book before it turns that way. The writing was competent, but not really engaging or inspiring. The technical aspects were the same.

  Bottom line: more of a vacation book. You get it and you may even read it to the end if the vacation lasts long enough, but not memorable or interesting enough to care about what happens next.

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  I have to admit I had no idea what this book was to be about. I hoped maybe Jennifer Egan is related to Greg Egan, maybe A Visit from the Goon Squad is science fiction or at least something humorous. But it was about random characters (New Yorkers, no less) and their private lives and introspections. The writing was good, even compelling, but I really wasn't in the mood for it.

  Maybe I will retry later on.

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  I grew up with cyberpunk novels and I loved them! It made me feel thrilled, scared and hopeful about the future at the same time. So when I heard that William Gibson, father of cyberpunk, published this relatively recently, I thought I was going to see how cyberpunk evolves through the ages, post '90s, but before the true Internet age.

  I rejoiced at that heavy read-a-paragraph-three-times-to-understand style and with a name like Pattern Recognition I was ready for a feast! Only... the main character is a marketing consultant for company logos. The thing is fantastical, but not set in the future. In fact, it reads more like fashion-punk than cyber anything!

  It gets worse! The antagonists are weird and ineffectual, the tension a mere nuisance for the main character rather than a driving force, the end goal finding McGuffiny McGuffinFace, the details boring and not interesting to me. At all! And when things get tough, you have a Deus ex Machina person stepping in and solving the problem. And every character is a hipster! This book, the first of a trilogy, sucks!

  I felt personally betrayed when reading something so antithetical to my interests, yet written in the familiar Gibsonesque punk style. I had planned a deep dive in Gibson's work and now I am terrified that I am going to reread the books I loved as a child and find them just as pretentious and empty, with characters that believe themselves much cooler than they actually are. Was Henry Dorset Case just another self absorbed hipster and I failed to notice it because the cyberpunk was cool and I was a kid?

  Bottom line: I did not like it.

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  Children of Time spans several thousand years from the points of view of three main actors: the people on an ark ship, the ambitious scientist who wants to create new life and that of the new life. Adrian Tchaikovsky writes adequately the story of the intersection of interests of these parties while reminding me of some of my favorite books like Accelerando and Blindsight, with a pinch of Xenogenesis, but the book is not nearly as good as either of them. Pretty damn good, though!

  It might have something to do with my very high expectations from people reading the book and praising the hell out of it. The book is good, but not THAT good. Then there are the technical aspects which sometimes were so wrong as to take me out of the story. These are minor points, though.

  The main issue with the story is that you have a very personal point of view for the humans and something akin to a David Attenborough documentary for the lifeforms. The contrast is jarring. The scope of the book, though, and the ideas explored are very interesting and the story is very science fictions, in the sense that it asks that essential "what if?" question and asks it well. The answer is just a little dry, that is all. Also, under that pretext, the book is actually taking a hard look at our own history, future prospects and examines the nature of humanity. Just the stuff I like.

  As proof that I did like the book, despite my usual old man grumbling, is that I have put the other two books in the series in my to read list.

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  At 60% of reading The Ninth Metal, the work Miskatonic was slided into the story. Then some vague visions of interdimensional doors and huge eyes and tentacles solidified the intention to have this as a "Lovecraftian novel". And it may well be, perhaps the entire series will be more, but as it stands, simply hinting at cosmic horror is not Lovecraftian and having less than 5% of your story be anything than random hicks in Minnesota doing whatever they usually do almost doesn't make it sci-fi.

  Now, Benjamin Percy's writing isn't terrible and slow paced stories that evolve slowly to give characters room to grow are not bad. I just felt that this book was a story of hardship in a family defined by local metal exploitation that a comic book writer felt the need to make superheroey and then (why not) Lovecraftian for a better selling position.

  But there were other things that made me dislike reading the book. One of them is the endless back and forth between present and flashbacks. This sucks in movie form, in a book format it's even worse. You have to mentally switch context from whatever you were enjoying (or trying to) to something else while the author is answering questions that you never asked. Second thing is the characterization. Most people were terrible clichés, most notably Wade. Not only does he just randomly die, no one, including his loving wife, even mentions him again. The bad boy who grew a solitary and strong-silent sense of morality, the ambitious woman regretting not having children and finding one to save, the innocent requiring saving, the psychopathic villain, the angry henchman, the waiting woman (complete with a worthless and disposable male companion while doing so), the annoying story of a vague but global catastrophe but focusing solely on a small American town and so on.

  Bottom line: I kind of liked the idea of the story, but I would have seen it compacted in the first three to five chapters of a single book. While tired of the "coasty" types of stories we are inundated with from cinema and TV, I didn't really want to fall into the other terrible formula: the small American town, truckers, miners and waitresses doing cowboy politics.

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  We all know Frank Herbert for his science fiction work, mainly Dune, but before he became famous by publishing that, he wrote may short stories and novels. This collection published in 2013 holds four of the pre-Dune novels he never got to publish. I found the stories very Herbert, kind of dated and, except the first one's premise, non-sci-fi. Yet they show how the ideas that went through Herbert's brain evolved in time.

  The novels in the collection are: High-Opp, Angel's Fall, A Game of Authors and A Thorn in the Bush.


  It shows the irreverent cynicism that the author had towards governments and social systems, but with a yet unpolished writing style. The story shows how a brilliant man, stuck in the middle of the social hierarchy of a communist-like government is betrayed and then manipulated by various groups. As the strong '50s male archetype he manages to outsmart and outfight everybody.

  Angel's Fall

  This is an interesting story about a damaged air vehicle floating on a river while enemies are trying to catch and destroy it. It's not sci-fi, as the air vehicle in question is a floatplane and the enemies are Amazon native tribes. But if you thought I was talking about the jungle part of The Green Brain, I would understand, as it's basically the same story without the sci-fi elements!

  A Game of Authors

  A weird story about an American journalist travelling to Mexico for a story, while being manipulated and attacked by various interested parties. It felt really dated and not well thought through. The characters were a joke, particularly the female ones. It was supposed to be a "brave resourceful man" story, but it felt like a "clueless American still doesn't believe people would try to kill him" thing.

  A Thorn in the Bush

  This felt like the least Herbert story of them all, even if it did focus on the internal drive and motivation of people. It's the story of an old madame who, having moved to Mexico and become respectable, tries to boss everybody based on her own past traumas and present delusions. Strange to have a female main character in a Herbert novel. It was not bad, but it was the farthest from sci-fi you will ever read.

With this I have ended reading everything Herbert wrote and I could find. From them all, Dune is of course on top of it all, but also Destination: Void (not the series, but the original book), Hellstrom's Hive, The White Plague and perhaps surprisingly Soul Catcher. There are lot of other good stories, but I loved these ones. Phew! It's over! :) It was nice, but a little tiring.

Note: This article is about Chromium based browsers.

Remember the days when computers were configured to present the filesystem to the network by default in read/write mode? Those were the days. Today, though, everything is configured for security and browsers are no exceptions. One thing that annoyed me yesterday was CSP (Content Security Policy) which disallowed me to fetch from a web site information from another web site which was happy to provide it. The culprit was a meta tag that looks like this:
<meta http-equiv="Content-Security-Policy" content="...">

The content was configuring default-srcconnect-src, style-src, frame-src, worker-src, img-srcscript-srcfont-src! Everything. But I wasn't looking for a hack to disable CSP (well I was, but that's another story), I just wanted to test that, given a friendly CSP, I could connect to a specific web site and get the data that I wanted and do something with it. Surely in the developer tools of the browser I would find something that would allow me to temporarily disable CSP. No such luck!

Then I looked on the Internet to see what people were saying. All were complaining about "Refused to connect to [url] because it violates the following Content Security Policy directive..." and how it annoyed them, but there was no real solution. Here is what I found:

  • browser extensions to remove the CSP header
    • I assume this works, but it wasn't my case
  • browser extensions to remove content from the page from the Developer Tools
    • I tried one, but when it changed the content now the browser was crashing with an ugly Aw, snap! page with a Status_Access_Violation status
  • I tried ticking the web site's settings for Insecure content
    • How naïve to think that it would allow loading of insecure content
  • I tried browser command line flags and experimental flags
    • nothing worked

I was contemplating hacking the browser somehow when I stumbled upon this gem: Override files and HTTP response headers locally.

It is almost exactly what I was looking for, only it doesn't replace content with regular expressions but saves the entire content of a URL on the local drive and serves it from there, modified in whatever way you want. So if you want to alter a server rendered page you're out of luck.

How did I use it to remove the CSP? I went to sources, I configured the local overrides and I then edited the page (in the Sources panel) and simply deleted the annoying meta tag. Now it worked.

Hope it helps!

Some time ago I wrote a post about the difference between temporary tables (#something) and table variables (@something) which concluded that before SQL Server 2019 table variables sucked. But I didn't give any real example. I made it very technical and clinical, perhaps creating the wrong impression that it's a matter of minute optimizations and not something somebody should know.

So gather 'round, children, and let me tell you the tale of the dreaded table variable! How a query that timed out after an hour was run in just 3 seconds with a tiny little fix. The server version was... 2017 (fade to dream sequence)

First, the setup: I needed to delete rows from a large table (30+ million rows) which did not have an associated account in a calculated list of about 20 thousand. Simple right?


SELECT ... whatever
FROM MyTable t

Just get me that first orphaned record please... ... ... 40 minutes later... WTF?

As I was saying in the previous post, table variables do not have statistics and the engine assumes they have only one row. So what does the execution plan want? To go through all of the 30+ million rows and then search them into the accounts table. Only the accounts table has 20 thousand rows, too. And it takes forever!

Mind that I've simplified the case here. Table variables do allow indexes and primary keys. I tried that. No effect at all!

Let's change the query then:


SELECT ... whatever
FROM MyTable t

DROP TABLE #Accounts

Just get me... wait, what? The query ended in 3 seconds. Suddenly, knowing the number and structure of the rows in the table led to the correct execution plan.

But can't I use table variables somehow? You can, but you have to force the engine to do it your way. First of all, you use OPTION (FORCE ORDER) which will keep the tables in the order you declared them. And then you have to reverse the JOIN so that @Accounts is the first table, but the effect is the same.


SELECT ... whatever
FROM @Accounts a

Back to three seconds. Ugh!

Now, I will probably use a temporary table, because forcing the way the SQL engine interprets your queries is almost always a bad idea and it makes the code harder to read, too.

Hope it helps!

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I am here to show you how to install whatever UCI compatible external engine you want and run it directly into the web site. The feature is still in alpha state (that means they guarantee nothing and have a lot more work on it), but it works pretty well.

Long story short

Here are the steps you have to follow:

  • Go to fitztrev's lichess-tauri (Lichess Local Engine) GitHub project, to Releases
  • Download the newest version of the app (at the moment of writing version 0.0.5) for your operating system
  • Run the installer and run the application
  • Log in to Lichess
  • DO NOT click on the Install Stockfish 16 button
  • Download the version of Stockfish (or any other UCI-compatible engine) that works best on your machine
  • Only then click on the Or add your own engine → button
  • Choose a descriptive title for the engine
  • Click on the Select button in the Binary section
  • Select the binary file for your preferred engine
  • Now you can go to and select whatever engine you configured in the Analysis/Study hamburger menu on the right side (bottom)

Short story long

Here are the steps you have to follow, with pretty pictures and extra information. Also a video at the end.

Go to the Releases of the Lichess Local Engine GitHub project

Go to this link: Releases.

Click on the title of the latest version (which should be on top).

Download the newest version of the app (at the moment of writing version 0.0.5) for your operating system

For this example, if you are on Windows, you should select the Lichess.Local.Engine_0.0.5_x64-setup.exe. 

Run the installer and run the application

Next, next, next:

Login to lichess

In order for this to work, the application needs access to the Lichess API, which functions with OAuth2 to authorize you. All you have to do is click on Log in with Lichess and follow the instructions.

DO NOT click on the Install Stockfish 16 button

Now you should be in the Add a chess engine section. While you can just click on Install Stockfish 16 and not care about things, choosing the engine that works best for your machine will save you a lot of time and resources. Besides, if you are reading this and installing Lichess External Engine, then you probably already have some chess GUI and some engines that you've installed before.

That is why I recommend you just add those or download them and then add them.

Download the version of Stockfish (or any other UCI-compatible engine) that works best on your machine

For example, the Stockfish engine download site shows this:

For me, the best verison is the AVX2 version while the one embedded with Lichess External Engine is probably the most compatible one. Note that there are specific binaries for particular CPU architectures. Just choose the best one for you.

Click on the Or add your own engine → button and set up your engine

The only important part for now is the title, so choose one that is telling you exactly what you've got. For example Stockfish 16 AVX2, because as new engine versions come up, you will perhaps have more versions of the same brand. The architecture is also relevant, as you may forget in a year or so which one was best for your machine.

Now click on Select and choose the binary file for your preferred engine.

Go to Lichess

You can use this external engine in the Analysis page or in a Study, where the same analysis control is being used, but I recommend you use it in Study because whenever you change the analysis engine the page refreshes, which in Analysis is deleting the moves you've made so far. BTW, shameless plug: if you had installed the LiChess Tools browser extension, then the PGN of the moves remains stored in the textarea under the board in the Analysis page and you can just reload it, no harm done.

The choice for engine is in the options menu of the Analysis, which can be opened with the hamburger menu button on the bottom of the move list.


So under the ENGINE MANAGER section you can select which engine you prefer.

Possible issues

You are now ready to do analysis with the new engines. However, since it is in alpha, there are some issues that have not been resolved and you might find them annoying.

  1. the engine doesn't know when to stop for some engines
    • this works fine with Stockfish, but not with Rybka 4.1, for example. 
    • let say you open an analysis page, import a game, start analysing, then stop. You would expect the engine to stop, too, but it doesn't. Closing the window doesn't help, because it's the Lichess External Engine application that runs it and it doesn't yet have a Cancel Analysis button.
    • the same applies to selecting other moves in the Lichess move list. The engine keeps analysing the previous move and it fails to connect to refresh the current move.
    • the solution is to close and restart Lichess External Engine, then enable analysis.
  2. the page gets refreshed whenever you change the engine
    • I am sure they are going to change this in the future, but at the moment this means it's better to use Studies, as they persist the moves in the list. Or LiChess Tools, of course.
  3. there are some people complaining that only the main moves (moves in the mainline) are getting analysed, otherwise the engine freezes
    • this was not my experience. Yet, in some cases, when the position had a cloud cache, I had to press the + sign (that runs the local analysis anyway) twice. It may be my setup, since I am also running LiChess Tools, but it wasn't that annoying. Just press multiple times if you see it doesn't work.
  4. when going deeper on cloud evaluations, there is no visible feedback
    • this affects me directly, because the engine is running, the page shows nothing and LiChess Tools is trying to go deeper all the time. But the engine is working in the background, doing who knows what.
  5. the server is sometimes unavailable
    • 503 errors from the server. I am sure they are working on features and it will happen a lot. However the client code doesn't handle that very gracefully.


I am sure that all of these issues will be resolved in time. I am so happy to see this feature, as the normal JavaScript Stockfish 14+ engine was extremely slow compared to the version run natively on my machine. Of course, there might still be the case that you want to continue the analysis on dedicated tools, but so far I am so in love with Lichess that I want to do everything there and share stuff with others.

In order for the developers to solve these issues, feedback is VERY important, so don't be shy and leave comments of all the issues you encounter and all the features you want to see and all improvements you can think of.

I leave you with a video from US Chess: John's How-To's: Using Engines on Lichess


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The Grob Attack, named not after the word grob (coarse, rough. uncouth, rude, crude), but from Swiss IM Henri Grob, who analysed and played it his entire career, is defined by the opening move 1. g4?. That's not a question, that's the mistake sign for a move in PGN syntax. Lichess sets it automatically on any analysis as the computer evaluation goes to -1.5. The opening's Wikipedia page opens with a quote from IM John Watson who calls it "masochistic", a move that could only appeal to people who enjoy pain.

And yet, the statistics of this opening tell a different story altogether.


For the entirety of the games in the Lichess stats, the Grob opening loses more than it wins, but it's 47% wins vs 49% losses. And once you refine the search, things become more interesting. Let's remove the 400 rating player bracket. Suddenly it's 48-48. Let's remove the 1000,1200 and 1400 bracket: 49-47; it's winning! OK, maybe we should look at every bracket in isolation (and imagine Hans Rosling presenting):

  • 400: 40-54, a massive loss which influences the entire statistic, even if it can hardly be called chess at that rating.
  • 1000: 43-52, amateurs do not do well starting with such a move, obviously.
  • 1200: 46-50, at this level chess is real, but Grob still loses.
  • 1400: 47-49, same as the general statistic. What is going on?
  • 1600: 50-47, a massive jump!
  • 1800: 49-47, is this an opening that only works between 1600-1800?
  • 2000: 49-47, a rating I can only dream of for myself and Grob is still ahead!
  • 2200: 48-47, what?!
  • 2500: 47-47, at the highest level of chess, 2500+, people win as much as they lose with this opening.

From now on we will stick to all chess games over 1600 rating, for quality, and without Ultrabullet, which is not chess.

You will say: you can always start with the Grob and transpose into one of the more common openings. I mean, people probably don't play 1. g4 d5 - the Grob gambit, they don't follow with 2. Bxg4 c4 - the Fritz gambit, right? You would be wrong. That's the most played line and the line that Stockfish would go for. And guess what, the winning statistics change to 56-40 after this sequence of moves, even while the evaluation is -1.7!

But, you will say, you're probably not looking at the Masters database for a reason. I am sure there is a refutation for it! Well, yes, Stockfish seems to think so, yet at every level this opening seems to be slightly better for White. Even at 400-1000 rating level once it reaches this Fritz gambit position the win ratio is 56-42 while at 2500+ rating (2000 games) it's almost equal.

So why does it happen? Why is Grob so successful? I am going to tell you. It's because Black doesn't play c6 and doesn't protect the d5 pawn. Or they blunder a piece :) That's the prize in this opening. You either get d5 or pivot immediately to another plan as White, and you better defend it as Black. And most of the moves to maintain the advantage feel unnatural to humans.

Then why does White lose if this is so good? Usually because they lose tempi. This opening is like the movie Crank, you have to move or die. Nc3 is essential, d3 to free the bishop and if somehow Black blocks the h1-b8 diagonal, then Nf3 or Ne2 is again necessary. But will you have time to make three development moves after your queen did everything while Black developed? 

I will begin, unusually, in Grob style, with the Stockfish refutation. It's interesting, but hardly easy to "feel" it as a human being. I will then continue with the general plans. Then show you twelve different traps, the first being the main line!


At the beginning of the game, right after 1. g4, c6 is a completely dumb move as it loses all White advantage. It doesn't develop and blocks an important development square. What about after 2. Bg2? It still loses a point in evaluation because White can now protect the g4 pawn. But after 2...Bxg4 3. c4, the move 3...c6 is what Stockfish recommends while also being the most played move at 2500+ levels. It's such an ugly move, though. Who, having not been studying this opening, would move a pawn to block the natural development square of the knight, delaying king castling even more, moving another non central pawn?

Well, one might argue that after the next best moves 4. cxd5 cxd5 the square is freed, so no biggie. But after 5. Qb3, Nc6 is still not available because b7 is hanging. Better defend it, right? Wrong! 5...Nf6 is the best move by far according to Stockfish, defending d5. So the continuation must be 6. Qxb7, right? Wrong again. 6. Nc3 for White, attacking d5, inviting d4. That move would be disastrous, leading to +4.5 eval since Black cannot save its rook. So what is the best move here? Nc6 is top 2, finally playable, but White will scoop that d5 pawn.

The second top 2 move is 6...e6. Another pawn move. The d5 pawn must be defended! Or rather, the diagonals to f7 and b7. The computer can't really decide on which of these moves is better, but more often than not it says e6 is superior to Nc6.

Can you reach this point and not consider this opening exciting?

Let's take a step back and check that b7 pawn. Can't we take it with 6. Qxb7? We push the knight to a more passive square which also blocks the Black queen's defense of d5, we gain a pawn, we block the rook since it has to guard a7, nothing can attack our queen. And indeed, it's the closest best move. However, the moves Nc3 and d3 are essential for White in most lines at some point or another. Let's be adventurous and kill the b7 pawn, followed by 6...Nd7 only move. The computer eval is still... -2. Stockfish is certain Black is better, because White has only developed a queen and fianchettoed a bishop, while Black has one center pawn, two knights and a bishop out and two open files for the rook.

7. Nc3 is the only move now. Develop as fast as possible. Black has the initiative, you have to take it back. If we take the d5 pawn now, with the bishop, we lose the bishop when the rook attacks the queen. Qc6 is met with Rc8 which either loses the queen or leads to mate.

So 7. Nc3 Rb8, attacking the queen and leaving the a7 pawn undefended. Should we play Qc6 like a computer or take the pawn? Not that much difference in eval, let's take the sucker! We are being greedy. 8. Qxa7 e5. Only move!

Why didn't e5 work a move before? Because our queen was attacking d5. Remember d5? Black has sacrificed the a7 pawn to protect d5 and we went for it!

But... d5 is still undefended. Both knight and bishop attack it, while the Black queen is blocked by the knight we force-moved there. Why not 8...e6, then? Wouldn't that free the bishop and also defend d5? Because Black's best play here is to try to coral the White queen. Black is still better with e6, but with less than a pawn. A move like e6 allows Qe3, escaping from the war zone into the safety of its troops. e5 on the other hand leads to a fork after Qe3, winning the knight. 

So we take another pawn! 9. Nxd5, so juicy! White is two pawns up, including d5, yet the eval is now -2.4 ?!

This line is not the Stockfish main line, but it's pretty damn close. All Black moves are computer generated while for White I've selected slightly (<0.2 eval difference) worst moves, but more greedy.

This position is amazing! Look at it! The Black queen side is devastated, White plays with just three pieces, both kings are in the center and with no prospect to castle any time soon, if ever, and the only centralized minor piece White has is about to get captured. It's, again, the only move to maintain the advantage, even if it exchanges a minor piece whilst two pawns down. Black cannot stand before two heroes on the board! So many unnatural looking moves just to keep that -2 advantage for Black. If you didn't read this post, you would never have made them, right? So, 9...Nxd5 10. Bxd5.

Black is now using its initiative to explode outwards. 10...Bc5, with tempo, attacking the White queen. The hunt begins! Qa4 and Qa6 are the only available moves, we use Qa4, best, for pinning a knight to the king and long-attacking the bishop. Rb4 is the best move, attacking the queen again and protecting the bishop in the process, yet the second best move is more positional: Bf5, taking the c2 square from a retreating queen. But we go with the best 11...Rb4. What is White to do?

The queen can retreat into a pin (Qa3), hide itself between Black pieces (Qc6) or stick itself right in, with Qa8, which is actually the best. All others are mistakes. This is the price of the hero queen: once cornered her skill and power does not matter, she will be hounded by minor pieces until she dies. The only solution, exchange itself for the enemy queen: 12. Qa8! There are tears in my eyes. I loved that queen! But the rook interferes again: 12...Rb8. Only move! Any other move brings the eval from -2.7 to 0 or better for White. The queen survives, as it retreats again at Qa4 and forces black to go with the positional move Bf5 instead or accept a draw by repetition.

14. Nf3 and White is finally getting out other pieces. Black's queen hunt failed, they castle short, bringing the king to safety. Yet our hero queen is not done. She follows the Black queen in a quest for mutually assured destruction: 15. Qh4. When having material advantage, exchange stuff. If the Black queen were to capture, the eval would go to +1 for White. So 15...Be7 16. Qh5 {attacking the bishop} Bg6 {attacking the queen} 16. Qh3 e4 {attacking the knight} 17. Bc6 {attacking another knight} Nc5 18. Ne5 Qd6 {attacking both knight and bishop if knight leaves} 19. Qg3 {defending the knight which defends the bishop} 

It's madness. After 20 moves the position looks like this: White has a queen and two minor pieces out. Every other pawn and piece on the board (including the king) have not moved at all. It's like White is playing blitz... krieg! Time is all that matters. If White loses tempi, they are lost. Black, on the other hand, is two pawns down, has all pieces out, the king castled, a pawn well advanced into White territory. Evaluation is now -3.5.

This is the "refutation" of the Grob Fritz gambit: a very positional computer-like play that no human would use or, if so, would actually enjoy playing.

The first chapter in the study below is the cinematic version of what I wrote above.


Every good opening has a plan. The Grob has some, but they are crude, coarse, uncouth, perhaps even rude. It counts on the fact that the opponent will either drop a piece, fumble their rook or trap their knight or even their queen. The goal of the opening is to equalize, winning the game is just the cherry on the cake. Here are some ideas for White:

  • invite the opponent to overextend pieces to places they are not so well suited for, then isolate or even trap them
  • harass the queen side, thus keeping the king side locked
  • prepare very long range attacks, from the fianchettoed bishop and the wayward queen, giving the opponent chances to hang pieces
  • always attack the rook in the corner, but the objective is not to actually take it, but to distract
  • once the light squared bishop is spent or neutralized, switch to attacks on the semi-open g-file
  • after the queen has stopped attacking by herself, the queen-side knight is essential to support her retreat or subsequent attacks
  • once material advantage has been secured, the position is probably bad, so exchange pieces as much as possible
  • this is NOT a king attacking opening, instead it is a royal killing spree attempting to get opponents out of preparation and into a bloody melee
  • there are two endgames with the Grob: the first phase, where we hope to distract and severely wound our opponent, then the actual end game, where we must convert the situation to a win

Check out the chapter Plans in the study above for examples of some of these ideas.

Traps and all kinds of fun

I've identified twelve traps, I am sure there are more, which stem from the Grob opening. There is a chapter for each of them in the study above, which is much better enjoyed on the Lichess website. There are some openings that really get one out of the Fritz gambit or even most ideas Grob, but I didn't see any reason why this opening would not be viable. Think of it as the Death Star: in order to refute it you must fly into a very tight canyon, defended by laser canons, and fire into an exhaust pipe, otherwise all is lost.

The master player who made use of this opening a lot, winning many games, is Michael Basman. Check out his games to see how a real pro does it.

Check out the Romford Countergambit chapters. It is a fun response to the Grob and a friend of mine has prepared a detailed video on it, which you can check out below, so expect a battle of openings!


Hope you had fun!

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  I developed an extension for Chromium based browsers that enhances and expands the functionality of the web site. Called LiChess Tools, it has so many features that I am sure people are overwhelmed by them and don't know how to use them all. In this blog post I will explain what the Explorer Practice feature is and how it can help anyone master any opening. Let's dive in.

Long story short

  In order to do this you need:

  • a Chromium-based browser like Chrome, Brave, Kiwi and so on. (the latter also works on mobile devices while allowing browser extensions)
  • installing the LiChess Tools extension in it (don't worry, it's completely free, ad free, spam free, open source, MIT licensed)
  • go to the website to the Analysis board or Study pages
  • open the Opening Explorer and click on the little button on the top left side to enable Explorer Practice

  Explorer Practice is exactly what it sounds like: it uses the information from the Explorer database to play the moves of the opposing side. This works for the Masters tab, for the Lichess tab (where you can select the type of game and player level range as well) and even for the Player tab, where you can train to play as or against a specific lichess player. You can even play against yourself! How cool is that?

  At the very end, when you reach a position not in the lichess database, a computer evaluation will reward you with a smiley for your efforts. This feature, like all other LiChess Tools features, are fully customizable on the Lichess Preferences page.

Short story long

  So let's go through a concrete example. As a total chess noob, I want to learn an opening that will take everyone by surprise. I will probably not find a lot of informational videos about it, since it's so rare no one knows about it. I will not find books or blog posts about it, either. All I have to go for is a name: Grob's Attack! It sounds so cool that I am ignoring its entry in Wikipedia that says:

International Master (IM) John Watson writes, "As far as I can tell, 1. g4 is competitive with 1. h4 for the honour of being White's worst first move. Against an informed or skilled opponent, it is simply masochistic."

  Let's follow the steps then. You obviously have a browser and you have installed LiChess Tools already. So let's open

  The simplest way to start is to go to the Tools menu -> Analysis board. Just clicking on the Tools menu gets us there. The same things work for a Study chapter, with the difference that the Study feature will preserve your moves (so you can create a repertoire as you play) and also it will show the Explorer moves. Using the Analysis board is considered more of a fun game, so the Explorer moves are hidden while Explorer Practice is enabled. Let's open Analysis:

  The Opening Explorer is a Lichess feature that tries to find the current position in the database and display the most common moves, winning statistics and recent notable games that reached it. You toggle it by clicking its button  or by the key shortcut E.

  Note the little tab-like button on the top-left corner of the explorer, the one with a target hit by an arrow (). It will toggle the Explorer Practice feature provided by LiChess Tools. You can also use the key shortcut shift-L, to align with the lichess L shortcut which toggles the computer evaluation.

  Before we enable Explorer Practice, though, we must choose our opponents. Since I am a noob I don't want to test my opening against grandmasters, only other amateur players, so I am going to have to select the range of players and type of game I am looking for. You do that by clicking on the small cog button on the top-right of the Explorer window (). This allows us to select, let's say, players up to 1400 rating and only in blitz games. You can, of course, leave all games on, but be warned, dedicated players often play bullet and ultrabullet to hone their skills and selecting those types of games will increase the level of difficulty, while also providing a lot more games to choose for.

  Now we are ready. Close the Explorer settings and click on the Explorer Practice button. As explained before, the list of move statistics disappears, but we can finally test our opening. Move 1. g4, which defines the Grob opening. There! Black moved automatically. And not some computer brilliancy, 20 moves deep and impenetrable even when they try to make a bad move. No, these are actual human moves.

  Once you finish the available moves, a smiley (sad or happy) will be your reward.

  Oh no! I am such a noob.

  Play again and again and again and learn how other people react to your moves. But sometimes you need some computer evaluation. Guess what? You can play the moves while the computer evaluation is running! It's not cheating, you are not actually playing, you are learning! Compare any move you make with the computer evaluation, learn what is best when you are not sure how to continue.

  In the end, remember that all feature of LiChess Tools are customizable in the Preferences page. You can turn them on, off or choose various parameters for them. For the Explorer Practice you can turn it on/off, but also can choose whether to show the smileys at the end of a run.

What then?

  If you trained the opening in a Study chapter, you now have a huge branching repertoire PGN chapter. You can start to analyse it for patterns. Use another cool LiChess Tools feature: auto evaluation. Just right click on any of the moves and select Evaluate terminating moves. The local browser engine will start analysing all of the last move of every branch and write a comment with the computer eval. Now you can see how successful you've been.

  Also, if take back the last move before you ran out, you usually get just one or a few games in that position. Looking at the rating of the players can give you an idea of your current chances against opponents of that level.

  Are you kicking ass? Maybe it's time to increase the level of your opponents! Or maybe it's time to select that friend of yours who always beats you at chess and train against his signature moves!

  Good luck and let me know how it went! I love to get feedback from people.

  If you got this far, I will gift you a warning and a bonus game from a practice session. The warning is that I've been playing around with Explorer Practice and it is very addictive! Be warned :) And now the game:

LiChess Tools is a Chromium-based browser extension (meaning Chrome, Brave, Edge, Kiwi - which also works on mobiles - and others, as long as they have a Chromium version equal or higher to 111) that extends the functionalities of the web site. This page is the user manual for the extension, cataloguing all of its current features and explaining how to use them.

All of the features below can be individually turned on or off from the Preferences menu, the LiChess Tools menu entry. Note that many of the options will be hidden until you toggle Advanced Preferences - these features will be marked with Advanced in the category section.

Here are the available features in LiChess Tools v2.2.8, in the order of decreasing approximate importance:

Extended interactive lessons

category: Study
values: Play all variations/Show score/Study links in comments in same window - defaults to all

This feature may be the flagship of the extension, as it allows you to play an Interactive lesson chapter by going through all variations instead of just the mainline. The default lichess behavior is to only follow the mainline, considering all sidelines as bad. With the new behavior all moves in the PGN tree are good, while the ones missing are bad. You can mark the bad variations with glyphs (good move, mistake, blunder, etc.), for example, to indicate if a move is bad or good, but you can continue playing it to see why. 

There is a mechanism to choose what the computer will play next as your opponent. It uses the number of branches in 8 ply (4 chess moves for both players) to determine which is more probable. This value can be changed (see Next move probability depth feature) For example if you have something like 1. e4 (1. d4 d5 2. Nc3 (2. Nf3)) 1... e5 2. Nf3, the mechanism will see that there are two possible branches for d4 as opposed to one for e4, so it will choose d4 66% of the time. The probability can be changed manually by adding a comment in the move with the format prc:<number>, where the number is a percentage between 1 and 100. Also, if set in the Transpositions behavior feature, the moves can be picked from moves following transposing positions. 

When hints are not provided by the study creator, one will be generated to show how many possible moves are available.

There is also a system to compute accuracy when playing an interactive lesson by counting the good and the bad moves. This will be displayed as a percentage at the end of the lesson and can be turned off by option.

The lichess UI remains the same, therefore the area in which to explain why any other move is wrong only appears on mainline moves. That is why this feature also adds a context menu item for nodes in interactive lessons to enable editing that information. As usual, when a "bad" move is made, the text to be displayed to the user will be taken from the first child (next move) of the current node (move). Therefore in order to make this work you have to right-click that node and explain why bad moves are wrong. This might be a bit counterintuitive, as you may have several moves following the current position, but the explanation has to be set to the first next move.


  • Play all variations - enables the Extended mode for interactive lessons, allowing you to play all variations with the computer picking random moves from the ones available in the PGN
  • Show score - shows the score at the end of the lesson. One can disable this to reduce frustration or for other reasons.
  • Study links in comments in same window - this makes links from move list comments which lead to studies open in the same window. The reason for this is that you want to continue a variation that is split into multiple chapters or that leads to another study in the same window, especially in Extended Interactive Lesson mode. Now you can utilize this with the Bookmarks option of the Move List Options feature to jump from move to move and chapter to chapter.

These options are also available in the action menu (hamburger button) of the Analysis board when in a study chapter that is of type Interactive Lesson. This allows to quickly enable/disable just these relevant settings.


  • one can play all variations of an interactive lesson with multiple branches only with the LiChess Tools extension installed, so if you create such a lesson only people with the extension can enjoy it. It would be nice to let everybody know that in a comment if you share it.
  • asking to show the next move will show a random move of the possible ones. Click on the button multiple times to go through more of them. Be warned that pressing the button is seen by the scoring system as a fail.

Ctrl-right to play random next move from list

category: Analysis/Study
values: yes/no - defaults to yes

This feature will allow you to play a random move by pressing Ctrl-right. There is a mechanism to choose what the computer will play next as your opponent. It uses the number of branches in 8 ply (4 chess moves for both players) to determine which is more probable. This value can be changed (see Next move probability depth feature) For example if you have something like 1. e4 (1. d4 d5 2. Nc3 (2. Nf3)) 1... e5 2. Nf3, the mechanism will see that there are two possible branches for d4 as opposed to one for e4, so it will choose d4 66% of the time. The probability can be changed manually by adding a comment in the move with the format prc:<number>, where the number is a percentage between 1 and 100. Also, if set in the Transpositions behavior feature, the moves can be picked from moves following transposing positions. 

Ctrl-left works almost like the left key, going to the previous position, but in this case it will go to the position you came from, not from the previous position on the line you've jumped to.


  • if set in Transpositions behavior, Ctrl-right may choose a move from another line, but made from the same position, which means that going "back" will go to the previous position in the current line, not the original one. Use Ctrl-Left to return to the position you jumped from. 
  • the keyboard shortcuts will be shown in the keyboard help popup if this feature is enabled

Behavior of transpositions

category: Analysis/Study - Advanced
values: exclude if same line/don't add identical next moves/play moves from transpositions - defaults to none

This feature determines what a transposition is for other features that use transpositions. The options are:

  • exclude if same line - two identical positions in the same PGN will not be considered transpositions of one another if they are in the same line of moves (one came before the other) (see Highlight moves in analysis and Show next moves from transpositions)
  • don't add identical next moves - when showing next possible moves at the bottom of the move list, if adding them from transposing positions, don't add the same move twice (see Show next moves from transpositions)
  • play moves from transpositions - when picking a next move to play, use transposing positions as well (see Ctrl-right to play random next move from the list and Extended Interactive Lessons)
  • none - when none of the values above are selected, any two identical positions will be considered transpositions, the move list can show multiple identical moves if they are coming from different transpositions/lines and the extension will not pick next moves using transpositions.

Next move probability depth

category: Analysis/Study - Advanced
values: equal/one move/two moves/three moves/five moves - defaults to 4 moves (8 ply)

This configures the mechanism calculating the probability of a next move in the PGN (see Extended Interactive Lessons and Ctrl-right to play random next move from list). The default value goes 4 moves for each player to see how many branches follow. It will then weigh each next move in the list based on that. If you want to turn this off completely, just select equal, which means it will not look at following moves at all. 

Variation arrows from transpositions

category: Analysis/Study - Advanced
values: yes/no - defaults to yes

This feature is showing variation arrows for transpositions, as defined in the Transpositions behavior feature.

Enhanced PGN import

category: Analysis
values: yes/no - defaults to yes

Another important feature of LiChess Tools, this one makes changes to the import mechanism in the Analysis board page. You can now import multiple PGNs at the same time and they will get merged into a single one. It is great for creating repertoires, analyzing the games of a specific player or creating Extended Interactive Lessons. From the Analysis board you can go to options and turn it into a study.

As part of this you will also get the Escape key functionality for the FEN and PGN inputs, blurring the input and allowing key shortcuts again.


  • the import mechanism in Analysis board ignores comments from the PGNs. This is a lichess limitation and to get around it I would have to rewrite the entire thing. I may do that, but it's not planned.
  • the import in Analysis board is different from the one in Studies. The one in Analysis board is client based, while the one in Studies is on the server. That is why I can only alter the one in Analysis board.
  • there is no logical limit to how many PGNs to import, but the Analysis board has a limit of about 5000 moves. Also, the API to turn it into a study has a size limitation, so if you try to turn a huge analysis to a study and it fails, know that it is too big. Highlighting moves on huge PGNs also is slow. So use with care.
  • From v2.1.21 the merge mechanism will check if the PGNs start from different positions and only merge what starts from the same position. Previously the merge seemed to be working, but it made no sense from the standpoint of PGNs, resulting in an invalid PGN that cannot be loaded.

Friends box

category: Friends
values: Default/Menu/Open/Hidden - defaults to Menu

This has evolved a lot. Originally it was automatically opening the friends box, but then several requests came that complained about the placement of the friends box and how distracting it was. So the current version of the feature can either:

  • Default - the default behavior of the friends list: stays in the bottom-right corner, only updates when opened, which requires a user click.
  • Button- the friends box is removed and replaced with a friends button, similar to the Notifications one. It will update in real time with the number of friends online and will change color when any one of them is playing.
  • Menu - the friends box is removed and replaced with a friends menu. It will update in real time with the number of friends online and will change color when any one of them is playing. It will also show the number of playing friends in a small blue square.
  • Open - the default behavior of the friends list, but it will open automatically when loading the page
  • Hidden - the friends list will disappear completely


  • clicking on the main menu item directly will open the friends page, but not on mobiles
  • when the width of the page goes under 972px, menus are grouped under a hamburger menu. The Friends menu will disappear and become a button in that case.

Live friends page

category: Friends
values: yes/no - defaults to yes

This is linked to the Friends box feature. The default behavior is to load whatever list of friends you have and then leave it at that. This feature will update the friends list in real time, while also allowing filtering by who is online, who is playing and (if player voice alerts are enabled) which player is muted. 

Each player will have a TV icon as well and (if player voice alerts are enabled) a mute/unmute button to include them in the alerts. (see Sound and voice alert with friends start playing)

Sound and voice alert when friends start playing

category: Friends
values: Ultrabullet/Bullet/Blitz/Rapid/Classical/Standard only- defaults to none

This feature will beep and spell out the player name and type of game they started. The type of the game can be chosen from the values. The definition of the game type comes from lichess, which assumes a typical game will be around 40 moves.

You can also choose which specific players to have the alert for, by going to the friends page and clicking the mute buttons. (see Live friends page)

If you select Standard only, then the alerts will only be sounded for the Standard variant of the game.


  • Chromium (and other) browsers disallow sounds from page load until the user does something like click on the page. In case an alert is attempted and audio is not allowed a red icon will appear next to the top buttons, which will disappear once the audio is allowed again.
  • The audio icon is part of lichess, which will also display it once sound is attempted but not allowed. At this time, the lichess icon will NOT disappear unless you click on it, different from how LiChess Tools uses it for alerts.
  • If you are playing a game on another tab, the sounds will not be played if the Quiet mode on all tabs feature is enabled.

Practice against moves from Opening Explorer

category: Analysis/Study
values: yes/no - defaults to yes

This is another great feature that allows you to play against whatever is selected in the Opening Explorer. Select masters to play against the best players, select Lichess and select the range of player to train against and select specific users to test your strategies against their played games. The feature can be turned on/off not only from Preferences, but also from the Explorer config screen.

In order to use this feature you need to go to the Analysis board or a study, open the Explorer and click on the icon next to the Masters tab, the one that looks like an arrow hitting a target.

The feature is unavailable in the Analysis screen of a running game.


  • you can toggle Explorer Practice by clicking on the arrow in the target button, but also with shift-L, to make it easier to switch between computer evaluation and the practice mode
    • the keyboard help popup shows this shortcut if the feature is enabled
  • the moves in the explorer window will get hidden in Analysis board, but not in studies. The motivation being that one is more like a game, with no lasting effects, the other is research.
  • if the Show emojis when out of moves feature is enabled in Explorer Practice options, then at the end of a run, when there are no more moves available in the Explorer for the feature to make, a quick computer analysis will be run to show you a smiley (happy or sad).

Explorer Practice options

Options for the Explorer Practice feature:

  • Show emojis when out of moves - set by default - will run a short computer analysis when out of moves in Explorer Practice, then show an happy/sad emoji based on the eval.
  • Click Explorer Σ to make a move - set by default - clicking on the Total row in Explorer will make a random move, weighted by the probabilities of the move (basically a one turn Practice move)

Highlight moves in analysis

category: Analysis/Study - Advanced
values: Last move in each variation/Not commented last moves/Transpositions to current move/Highlight board when out of main line - defaults to Last move in each variation/Not commented last moves

This feature will highlight moves in the analysis move list. Each option highlights a specific thing:

  • Last move in each variation - for each branch, highlights the last move
  • Not commented last moves - for each branch, highlights the last move that has no comment or is not a mate
  • Transpositions to current move - highlights positions that are identical to the current one in the same PGN (see Behavior of transpositions to change what the extension considers a transposition)
  • Highlight board when out of main line - dims the board a little when moving out of main line

Extra context menu options

category: Analysis/Study
values: Copy branch as PGN/Engine evaluation for last moves/Highlight all transpositions/Remove superfluous - defaults to Copy branch as PGN, Engine evaluation for last moves, Remove superfluous

This feature will add extra options to the Analysis board/Study move list context menu. The options are:

  • Copy branch as PGN - this works in Analysis board and Studies and turns all the previous moves of the line you are in, plus all the branches after the move, into a PGN in your clipboard.
    • If you press the Shift key when clicking on Copy branch as PGN the copied PGN will start from current position, not from the beginning of the original chapter.
    • If you press the Control key when clicking on Copy branch as PGN each variation branch will be copied as a separate PGN.
    • If you press the Alt key when clicking on Copy branch as PGN then the PGN will get copied only to the current position.
    • You can use it to split large PGNs by copying variations into their own chapters, then maybe deleting them from the original one.
  • Engine evaluation for last moves - this works only for Studies, because it involves move comments. It will go through all of the uncommented last moves and create a comment in the form eval:<evaluation> using the local computer engine. The evaluation will stop at the engine depth selected in Preferences (see Custom analysis engine depth).
  • Highlight all transpositions - this works for both Analysis board and Studies and highlights all moves that have transpositions. You can configure what a transposition is in Preferences (see Behavior of transpositions)
  • Remove superfluous - for purposes of saving space, this removes the following entries from the context menu:
    • Annotate with glyphs - there is a button for this under the board
    • Comment on this move - there is a button for this under the board
    • Copy variation PGN - LiChess Tools already provides a better version

Custom analysis engine depth

category: Analysis/Study - Advanced
values: a number representing the depth - defaults to empty

This feature will allow you to set a depth level for the computer engine. If the current move has a smaller depth level (let's say it was cached in the cloud with that level) it will start the local computer evaluation. Once it reaches the set depth, the engine will stop. You can restart the analysis by pressing the little + button next to the computer engine depth indication.

This feature is also used as the level at which to consider evaluation done for the Engine evaluation for last moves option (see Extra context menu options)

This feature is also used in Practice, where it controls the level of play (See Custom analysis engine options)

Custom analysis engine options

category: Analysis/Study - Advanced
values: Always use local engine for evaluation/Apply in Practice mode - defaults to none

This feature controls the behavior of the analysis engine used in Analysis board and Studies.


  • Always use local engine for evaluation - Use this option to never show computer evaluations from the cloud. For example if you want to not see evaluations over a certain level or in practice mode. You can also toggle this on/off from the Analysis board hamburger menu.
  • Apply in Practice mode - Use this to apply both the custom engine depth and the no cloud option before in Practice mode. This means you can play against a computer of your own level and ignore cloud and table bases. You can also toggle this on/off from the Analysis board hamburger menu.

Show next moves from transpositions

category: Analysis/Study - Advanced
values: yes/no - defaults to yes

When you get to a certain position in the PGN which has transpositions, the next moves from those transpositions will be displayed under the move list, just like for a fork into multiple variations. You can configure what a transposition is, as well as if you want multiple identical moves to be shown or not and if the moves in this list should be considered by Ctrl-right and Extended Interactive Lessons in Preferences (see Behavior of transpositions)

Extra key shortcuts

category: Analysis/Study - Advanced
values: yes/no - defaults to yes

this feature adds extra key shortcuts to the Analysis board/Studies:

  • first it changes the functionality of the i, m and b keys to work in Analysis board as well as Studies and to use all variations, not just the main line as the original lichess behavior. The functionality of these keys is to jump to the next inaccuracy, mistake or blunder, respectively
  • it adds the same functionality to Alt-i, Alt-m and Alt-b, only for the opponent
  • g and Alt-g cycle through good/brilliant/interesting moves
  • it adds the ability to select any of the moves in the available moves lists:
    • press . (dot) and then a digit and it will make to the nth next move available in the PGN (see Transpositions behavior if you want to select moves from transpositions, too)
    • press Ctrl-. and then a digit and it will make to the nth next move available in the computer evaluation list
    • press Shift-. and then a digit and it will make to the nth next move available in the opening explorer list


  • the keyboard help popup now shows all of these shortcuts if the feature is enabled

Additional glyphs

category: Study - Advanced
values: yes/no - defaults to yes

This feature displays an extra # glyph on mate moves. Also it enlarges glyphs on mobile devices.


  • The lichess UI allows for multiple glyphs on the same move. The one shown on board will just be the first one in the list.
  • Originally this feature was created to show annotations that lichess was not showing. From September 2013 lichess started natively showing all annotations, therefore eliminating the need for much of the functionality of the feature. Since the changes on lichess are volatile, this feature might need to go back and forth as well.

Extra analysis charting

category: Analysis/Study - Advanced
values: Material/Principled/Max tension/Max potential/Find interesting moves/Chart smoothing/on Eval gauge - defaults to Material,Principled,Max tension,Chart smoothing,on Eval gauge

This experimental feature is adding extra lines on the computer analysis chart. In the search for good/great/brilliant moves - as shown on and requested by a lot of players, the lines drawn over the normal computer eval chart are meant to give some indication of what is going on without asserting an exact significance of the values. The lines are purposefully left without explanation, in the hope that players recognize some aspects of the game in the numerical values charted and their intersection.

For example, many of the moves generally considered brilliant see a steep increase in evaluation, but a steep decrease in material and/or principled position, indicating a sacrifice or an unnatural seeming move that wins the game.

If Find interesting moves is enabled then an extra entry in the analysis summary shows the total of interesting/good/brilliant moves in the PGN. The feature will also attempt to find such moves automatically.


  • Material - green dashed line shows a more classical material difference between the sides
  • Principled - blue dashed line shows how principled the position is. This means stuff like square control, freedom of movement, developed centralized pieces, etc, but excepting material value.
  • Max tension - red dotted vertical line shows the point of maximum tension in the game. Tension here is defined as the total material that can be captured by both sides in just one move.
  • Max potential - green dotted vertical line shows the point of maximum potential (similar to tension, but it superficially looks at capture chains)
  • Find interesting moves - if enabled, this will show good/brilliant/interesting moves in the analysis summary as a link that cycles through them. It will also automatically find some categories of interesting moves and mark them with !? glyphs (if not already annotated). The glyphs added by this algorithm will be temporary (not persisted on the server).
  • Chart smoothing - if this is enabled, temporary spikes in the charts will be removed. Example: you take a bishop with a knight, the material jumps 3 points in your favor, but the next move the opponent takes your knight, so the material goes back to 0. The smoothing function will attempt to remove these meaningless jumps in material. 
  • on Eval gauge - if this is set, two lines (one green and one blue) will appear on the evaluation gauge when it is visible, changing with the values of material and principled values, respectively.


  • I called it "interesting moves" because there is no objective good/brilliant move algorithm. I will continue to work on it in the future.

Change chapter names from PGN tags

category: Study - Advanced
values: yes/no - defaults to yes

This feature will give you the option to quickly change the name of a study chapter to either the content of its Event PGN tag or the White and Black PGN tags combines when editing the chapter. Sometimes people want to import a series of PGNs into a study, but only the first chapter gets a proper naming from the PGN tags, the rest getting the default Chapter 2, Chapter 3... etc name. With this you can go to each of them, edit them by clicking the cog button next to their names, then choosing with one click the name the chapter should have.

Study chapter navigation controls

category: Study - Advanced
values: yes/no - defaults to yes

This feature will add a set of buttons at the end of the chapter list in a study. The buttons allow to navigate to the first chapter, previous chapter, random chapter, next chapter and last chapter respectively.

Sticky study Preview mode

category: Study, Interactive Lesson chapters - Advanced
values: yes/no - defaults to yes

This feature will keep you in Preview mode as you move from one Interactive lesson chapter to another. As one trains using interactive lessons, at the end of one they are presented with the option to move to the next chapter. The default lichess behavior is to show you the chapter in edit mode (assuming you are the owner or a contributor) which requires you to press the Preview button all the time to continue training, after also having seen the move list. Now you can press Preview once and play chapter after chapter with no hassle.

From version 2.1.51 on, this is preserved also between page reloads, so you will have to manually unset Preview mode to edit a study Interactive Lesson.

Show game opening names

category: General
values: yes/no - defaults to yes

This feature will load the lichess opening name for games and display it. When watching a game or analyzing it, the opening will be shown under the player names. For mini-games (the tiny ones that appear when hovering over a game link or put somewhere on the page) it will appear at the bottom. For Analysis board, if the wiki side is empty, it will show the opening there, assuming the position is in the local cache.

Show pawn structures

category: General
values: Enabled/Only named structures/Fuzzy search - defaults to Only named structures/Fuzzy search 

This feature is disabled by default because it's pretty technical, but I want to enable it in the future. What it does is, similar to Show game opening names, show the pawn structure of the current game. Because it's all very local, with no API requirements, it also works for current game pages.

An entire blog post about it can be found here: The Pawn Structure feature in LiChess Tools


  • Enabled - enables or disables the feature - disabled by default.
  • Only named structures - show only structures with names. This is enabled by default, but of course will not work unless enabling the whole feature. If you disable this, you will see a very technical name for each and every move.
  • Fuzzy search - this will show named pawn structures within a certain proximity. It helps to determine the general structure, even if it might not be totally accurate.


  • This feature has a lot of potential, as the pawn structure is something that informs medium to long term plans. Knowing these will help you grow a lot as a chess player.
  • If the pawn structure is named, it will show as a link which can be clicked to learn more.
  • If the structure is not found in the available list, it will be searched from the opponent's perspective, in which case it will be shown with a (R) at the end if found

Show player country flags

category: General
values: yes/no - defaults to yes

A very early feature of the extension, it has also evolved a lot. The latest version is much more efficient in terms of how it gets the data from the server and adds flags to almost every place where a user link is shown. I am aware that this might be distracting and I am planning some detailed values to choose how wide spread the flags will be. Also, did you notice the flags are lazily flapping in the wind?

Autosave analysis for reload

category: Analysis - Advanced
values: yes/no - defaults to yes

This happened to me a lot of times: I am analyzing something and I accidentally swipe the touchpad or press some key that reloads the page. All my work is gone! This feature keeps track of the latest modifications of Analysis board PGN and reloads it on page load. It is your choice if you want to import it or not by going to the PGN text area and clicking the Import PGN button.


  • The saved PGN as well as the Analysis board import text area content will be overwritten by whatever move you make, so if you fail to import the PGN and make a move, you lose the data. 

Opening explorer player features

category: Analysis/Study - Advanced
values: Me button to switch to your player - defaults to Me button to switch to your player

This feature controls the choice of the player in the Opening Explorer.

  • Me button to switch to your player - adds a tab next to Masters database, Lichess and Player named Me. If you click on it the choice of the player will toggle from your user to the last selected user.  The button can be shown/hidden from the Explorer config screen as well. 
  • Ability to remove players from the name list - adds the ability to delete players from the list of username previously chosen in the player tab
    • Lichess implemented this feature natively so it was removed from LiChess Tools in v2.1.21


  • The Me button will appear only if you have any another players configured for the Player tab name list

Toggle snapshots of Explorer settings

category: Analysis/Study - Advanced
values: yes/no - defaults to no

This feature will add a new button called Snap! in the Explorer settings of the Lichess database tab. This will allow to save the current Explorer settings under a name, then quickly toggle between the various sets saved by clicking on the same tab, which will now change text to reflect the name of the selected "snap". You can easily delete existing snaps and create others.


  • This is a pretty niche tool, so it's disabled by default. You have to manually enable it to try it out.

Various TV options

category: TV
values: Link for current TV game/Bookmark for current TV game/Streamers current games/Friends current games/Previous two games in player TV - default to all

This feature has been introduced in version 2.2.0 to merge four existing tools for TV with the same functionality. Make sure you review your Preferences.


  • Link for current TV game - adds a link to the currently played game in TV on the title, just like in Analysis mode
  • Bookmark for current TV game - adds the ability to bookmark a currently playing game by hovering the mouse next to the game title
  • Streamers current games - adds a Streamers tab in the Current Games page where you can see the games of all currently playing streamers
  • Friends current games - adds a Friends tab in the Current Games page where you can see the games of all currently playing players that you follow
  • Previous two games in player TV  - In category TV (when you are watching Blitz games for example) you get a list of two previous games in that category under the main playing board. For player TV, when you go to a specific player to watch their games, this is missing. This feature will add the two previously played games by the player you are watching.

Previously viewed game menu item

category: TV - Advanced
values: yes/no - defaults to yes

This feature adds an extra menu item in the Watch menu that will take you to the previously seen chess game. Just opening any game will consider it as watched. If you go to the previously watched game, then clicking on the menu item again will take you to the game you watched before that, and so on. The total number of remembered games is 10.

Last visited study menu

category: Study - Advanced
values: yes/no - defaults to yes

This feature adds an extra menu item in the Learn menu that will take you to the previously visited study. Just opening any study will consider it as watched.

Styling for study comments

category: Study
values: yes/no - defaults to yes

This feature adds the ability to style the comments in your PGNs. You can choose between a number of styles that you can place anywhere in a comment with cls:<styleName>. It also adds a new button next to the comment button in a study chapter (a quill in an inkwell) that with cycle through all of the classes at the very beginning of the comment to the current move. The usable classes are: red, orange, yellow, green, lightgreen, cyan, lightblue, blue, violet, magenta, pink, underline, strikethrough, italic, bold, cursive and nothing or clear to clear existing class.


  • the name of the class declares the intent, not the actual result of the styling. Given that there are dark and light themes on lichess, the styles have been updates to be readable in both situations, using shadows or slightly different colors.
  • the style of the comment will only be visible to you and people with LiChess Tools installed. All others will see cls:blue or whatever in the comment.
  • you can actually put anything as the class name and the comment will be put inside a span with the class lichessTools-<your class name>, which allows you to customize your style even more with the addition of custom styles from other extensions like Stylus. In this case all people seeing the comment would also need the custom styling.

Show the order of arrows and circles

category: Analysis/Study - Advanced
values: yes/no - defaults to no

This feature shows a number on each drawn shape, so that you can see their order. Sometimes in studies you want to convey the moves that could follow the current position using arrows and circles, but in certain situations the order of the moves is important. Set this to true in order to see which arrow comes first.

Ctrl-Space for best computer move

category: Analysis/Study - Advanced
values: yes/no - defaults to yes

The default functionality of the Space bar in analysis mode is to start the computer engine if not started or play the best move in the computer move list. Because I was often using lichess with YouTube in another tab, pressing Space accidentally was always an annoyance. This feature changes the shortcut to Ctrl-Space.


  • A previous version of the feature was using Shift-Space, but it would overlap with a lichess feature.

Clear chapter artifacts

category: Study - Advanced
values: yes/no - defaults to yes

This feature allows you to choose which artifacts to clear from only the current study chapter. To use it, click on the cog button next to the chapter name and, instead of the Clear annotations button now you get the choice of just comments, glyphs (good move, bad move, that kind of thing) and drawn shapes (circles and arrows) as well as all of the above. There is an extra option of clearing all PGN tags. This feature also adds individual delete buttons to all tags in the current study chapter.


  • this only works for the current chapter, as the site does not have access to the moves or tags in the PGNs of other chapters
    • the feature could be modified to work on all chapters, but it would have to first select the chapter, then alter it, which I think is not something that should be done automatically.
  • this works on the client, which means that instead of sending one command to the lichess site, it creates delete requests for each item. If the PGN is large, this can take a long time.

Customize chat buttons

category: Play
values: yes/no - defaults to no

When playing the first few moves and after the game has ended, lichess gives you the option to click on some buttons for some standardized message like Hello, or Have fun! This feature will give you the ability to customize these buttons.

The interface may not be the most intuitive. To edit buttons you click on the little cog button, to exit edit mode you click on the same. This allows altering, adding and deleting buttons. Click on the small X button to enter delete mode, after which you click on buttons to delete them. Delete them all and you get the default buttons back.

In order to add or alter buttons you have to write in the chat text input something like <name>/<message>. Example: hi/Why, hello there, old chap!, which will create a button with the text HI which will send the chat text "Why, hello there, old chap!". In order to add the button, you click the + button. In order to alter an existing button, you click on that button.


  • the name of the button can be only 2,3 or 4 characters long.
  • if you attempt to add or edit a button without a recognizably correct input text, the input box will jiggle to let you know you are doing something wrong
  • to edit the end of game buttons you have to reach the end of a game. This may be inconvenient and I am thinking of solutions
  • I am considering expanding this feature with buttons for the duration of the game as well as for spectators. Let me know what you think!

Timeline notifications

category: General - advanced
values: Forum post/Blog post/Lichess announcement/Stream start/Simul create/Simul join/Team create/Team join/Tournament join/Following/Study like/Blog post like - defaults to Forum post/Blog post

This feature will add a notification when there are unread items in your Timeline. The default values include comments on forum or blog posts you follow, forum or blog posts from people you follow. Basically posts that you wouldn't normally be notified about. 

Clicking on the notification will take you to the Timeline page. Opening it from here or anywhere else will consider the items read and so you will not see the notification until new ones turn up.


  • there will be no notification if quiet mode is on (meaning you are playing a game or you have quiet mode manually set)

Mobile device features

category: General
values: Evaluation gauge/Hide the octopus mascot/Analysis arrows/Random move button/Scroll lock when playing - defaults to Evaluation gauge, Random move button

This feature alters some behavior specifically for mobile devices. There are Chromium-based mobile browsers, like Kiwi, which accept browser extensions. Enjoy LiChess Tools on mobile installing one and then the extension, then customize the experience with this feature. The options are:

  • Evaluation gauge - makes the evaluation gauge visible even on small screen widths (for mobile)
  • Hide the octopus mascot - hides the octopus mascot that takes a lot of space in Interactive Lessons
  • Analysis arrows - adds a button next to the Explorer and Practice ones that allows for drawing arrows and circles on mobile devices in Analysis board and Studies
  • Random move button - adds a button between the previous and next move buttons that will randomly play a move from the move list (same functionality as Ctrl-right to play random next move from list on desktop)
  • Screen lock when playing - will lock scrolling and zooming on mobiles when playing (or during puzzles). A lock icon will appear as a button on top of the screen that you can tap to temporarily lock/unlock the scrolling on that page (refreshing or going to other screens will again automatically lock the screen until you unset the value from Preferences).


  • Because both the shape drawing and random move buttons take up space, this feature also changes the style of the buttons so that they take two rows of space: the first for utility buttons (left) and the hamburger menu button (right) and the second row for PGN navigation buttons (first, previous, random, next, last move). If none of the two options mentioned are enabled, then the regular "one row for all buttons" style is used.
  • Screen locking when "playing" doesn't necessarily means when playing, but when lichess is in "playing mode". For example that also means when you haven't yet started the game or when you just ended the game or when you are doing puzzles.

Mobile device game features

category: General - Advanced
values: Game arrows/Standard buttons - defaults to none

This feature alters some behavior specifically for mobile devices when in-game. This means playing, or solving puzzles or even watching running TV games. There are Chromium-based mobile browsers, like Kiwi, which accept browser extensions. Enjoy LiChess Tools on mobile installing one and then the extension, then customize the experience with this feature. The options are:

  • Game arrows - adds a button next to the Analysis board one that allows for drawing arrows and circles on mobile devices in games
  • Standard buttons - the default behavior of is to hide the move navigation buttons for games on small screens, instead showing one line of PGN with previous and next move buttons on either side. Set this in order to see all buttons (including the Game arrows one above). For normal play this is not necessary, but in puzzles, TV and such screens this is the only way to access the drawing arrows button.

Show evaluation of explorer moves

category: Analysis/Study - Advanced
values: From computer eval/From cloud/From winning stats/Hidden - defaults to From computer eval/From cloud

This feature will show the move evaluation for Explorer moves. This information is retrieved from three different sources that can be enabled or disabled: the local computer eval, the lichess cloud (or chessDb if lichess ever allows it) and the Explorer stats themselves. If Hidden is set, then the settings for evaluation will remain, but the column will not be shown. The feature can be hidden not only from Preferences, but also from the Explorer config screen. 

The statistics eval will only be shown if there are 100 or more games in the lichess database for that move and not all won by one side. Its faded coloring signifies that it's not a true eval, but if enabled can compare with the other values. 

Computer evaluations will have a white color, stats evaluations will have a grey faded color and the cloud evaluations will be slightly blue. If the chessDb option will ever be allowed, it will show either red, green or bright green for bad, good and best moves.

This feature also adds a warning icon on the right side of moves that have large differences between evaluation and winning stats, indicating a possible trap or gambit situation.

The feature is unavailable in the Analysis screen of a running game.


  • Unfortunately, the Content Security Policy (CSP) of lichess doesn't allow calls to, but I am using the data from lichess' cloud-eval API. I am trying to convince developers there to allow the domain, but I wouldn't hold my breath.
  • The more lines you have configured on your computer analysis, the more items in the list will be evaluated. Explorer can show 12 moves, for example, while the computer analysis is configured with Multiple lines=2, this means a maximum of 2 items in the Explorer will have an evaluation. With 5, you get 5, assuming the computer moves are in the Explorer list.
  • There is an internal cache of these evaluations, so you can run the computer eval for some moves, then stop it, but when going to those moves you will still see the evaluations as done before at whatever depth was last computed.
  • Take care with stats evals in positions with few games. It might tell you that you are absolutely winning, but that's just because no one played a winning move from that position. That is why eval from winning stats is disabled by default.
  • The evaluations from cloud differ in depth based on how many moves you want to see. For example you could ask for just one move (the best in the position) and it might show you the eval with depth 55, but if you ask for two moves it will give you depth 44, for 20 moves you would get depth 13 or even nothing. To account for this, cloud eval combines the values from two calls: for 5 moves and for 10 moves. Since the cloud data comes from local evals, server evals and different versions of Stockfish and I am combining two different depth evals, take the evaluation as an estimation, not a given.
  • Changing the options for evaluation in Preferences will reset the local cache for each move.
  • Lichess' cloud eval API will return 404 when no data is available, resulting in ugly red network lines and error messages in the browser developer tools. Those are not errors, but there is no way to hide them in Chromium browsers from JavaScript. If it annoys you, you can turn them off from DevTools (see
  • Depending on how much you do analysis and how overloaded the servers are, cloud eval might start returning 429 errors, meaning the servers report you are abusing them. A warning will appear every minute while that happens. The workaround is to disable From cloud and use just computer eval (which, of course, will also use cloud eval :-P). The configuration on lichess' side, at least for the moment, is 3000 calls per IP address per day. That's a bit low, but it might be enough.
  • If computer evaluation is started and used as a data source, the cloud eval will not be accessed.

Show explorer moves leading to gambits

category: Analysis/Study - Advanced
values: yes/no - defaults to no

This feature adds a new column to the Explorer table showing the number of gambits reachable from the current position and for each move to play. The feature can be turned on/off not only from Preferences, but also from the Explorer config screen.

The feature is unavailable in the Analysis screen of a running game.

Quiet mode on all tabs

category: Play - Advanced
values: yes/no - defaults to yes

When a game starts, lichess sets a quietMode variable to true, instructing various notifications to not be displayed. Unfortunately, that only happens on the page that one plays on. This feature makes all open lichess pages get the value for quiet mode from the same place, so they don't behave inconsistently.

There is also a button added to the lichess menu which can manually enable/disable quiet mode. Warning: once manually enabled, quiet mode will remain on until manually disabled! The normal game playing quiet mode will turn on and off automatically, as before, only it will affect all open lichess pages.


Colors for shapes on mobile

category: General - Advanced
values: 1/2/3/4 - defaults to 1

This is part of the Mobile Experience feature and it selects the count of colors you can use on mobile to draw arrows and circles. If you only want to turn the drawing mode on/off with a single tap, select 1.

Insert new chapter after current one

category: Study - Advanced
values: yes/no - defaults to yes

This feature adds a button to the create study chapter form with the text Create after current. Using this button instead of the normal Create chapter will create the chapter immediately after the currently selected chapter.

Show PGN in studies

category: Study - Advanced
values: yes/no - defaults to yes

This feature adds a textarea in the study Share tab called PGN. Similar to the one in Analysis board, it will show the PGN text of the current chapter. The PGN will be generated by the same code that generates the one from Extra context menu options and may differ from the one generated by the Copy PGN or Download PGN buttons.

Persist settings on study create/edit

category: Study - Advanced
values: yes/no - defaults to no

This feature will persist the settings for studies when you create or edit them. Then it will use the same values when creating new studies.

Also save options for browser private/incognito mode

category: General - Advanced
values: yes/no - defaults to no

This was a user request to find a way to save the options outside the local browser cache, as he was playing the game from incognito/private browser mode. Since no other solution was better, this saves the options as notes in the first chess game you ever played on lichess. So be careful that this will alter those notes, although I am not aware of many people using the private notes feature.


  • be aware that it will alter the private notes of the very first game you played on lichess
  • the extension will use whatever options you have in the browser local cache. Only if they are not there it will take them from the notes. That means that you can do weird stuff like enabling the feature, saving options, disabling it, changing the options and now you will have different settings in normal and incognito mode. So use with care.

Move list options

category: Analysis/Study - Advanced
values: Indented variations/Bookmarks/Expanded move list/Hide left side/Open in new window/Eval button on the right - defaults to Bookmarks

This feature will change the functionality or appearance of the move list in Analysis board. There are already such changes with the Highlight moves in analysis functionality.


  • Indented variations - this will make even variations that follow in line (when they are less than three, they are displayed one after the other in parentheses, like in a PGN text) show as tree branches, increasing readability and preparing for new features that will use this.
  • Bookmarks - Study only - this will allow for bookmarks, which are very cool (read below), but a bit experimental. Let me know how they could be more of use to you.
  • Expanded move list - Only for desktop resolutions (1260+ px), this feature is removing the left and right margins and expanding the move list to the edge of the screen and also downwards. It is meant to allow analysis on very complex PGNs.
  • Hide left side - Most of the time the left side of the analysis screen is useless: chat, notes, study participants and stuff like that. With this, you can hide that side to gain even more space for the move list. This is intended to be used together with Expanded move list, but you can use it separately as well. 
  • Open in new window - Study only - this adds a small button in the top-right corner of the page, just before the computer evaluation toggle. Clicking it opens a new window with just the analysis tools (move list, computer eval, explorer) that you can move to another monitor, for example, or resize and place wherever you want. Use the study SYNC button to keep the two windows synchronized. (the SYNC button only appears under the board when the study is set to Enable sync)
  • Eval button on the right - this will move the computer evaluation button to the right side of the eval header and also make it a little bit smaller.

How bookmarks work:

  • right-click on a move in a study move list and select Add/Remove bookmark from the context menu
  • put any text in the textbox that appears (or remove it all to delete the bookmark)
  • this will create a bookmark, which serves several purposes:
    • it will show as a named label in the move list (good for naming variations or making the PGN more readable)
    • it will allow to expand/collapse the branch from that move on
    • it will serve as an anchor for URLs to this exact variation
  • for any bookmarked move you can right-click it and get:
    • Collapse/Expand all bookmarks - collapse and expand all bookmarks in the tree
    • Get bookmark URL - will copy to clipboard a URL to that specific move in that specific chapter and study (the link will look like this:<studyId>/<chapterId>#<bookmark name>)
    • Split chapter here - only if the bookmarked node has children (following moves) - it will create a new chapter with the following moves, then add a comment with the URL to the new chapter. If you want to also delete the following moves, press Shift when you click on the menu item. The confirmation dialog should reflect that moves will be deleted.


  • Bookmarks are saved in the comments as bkm:<label>
  • Only you and people with the LiChess Tools extension (and bookmarks enabled) can see and use the bookmarks, the rest will just see the bkm:<label> in the comment
  • Splitting a chapter with Shift-click DELETES THE EXISTING FOLLOWING MOVES from the initial chapter. Don't tell me you weren't warned.


category: General - Advanced
values: whatever themes are available - defaults to none

This is an experimental feature, the purpose of which is to accept user CSS themes as part of the extension.

Available themes:

  • Performance - performance CSS changes, mainly attempting to remove all animations, which cause slow rendering
  • Just Explorer - will hide the computer eval moves (but not the arrows, if enabled) and the move list when the Explorer is open. This will only be applied for mobile devices
  • Mobile - a lot of style improvements for mobile, especially aimed at studies and interactive lessons
  • Move colorizer - Each level of PGN moves is colored slightly differently and comments are italicized


  • The maintainer of the theme will be acknowledged in the Preferences page
  • I have no skill to maintain CSS themes, so whoever makes the theme, if it meets with a minimum approval from me, will have to maintain it. A problematic theme with no signs of maintenance will be removed.
  • Multiple themes can be applied at the same time, but beware of conflicts. 

Wiki pages based on FEN

category: Analysis board - Advanced
values: yes/no - defaults to yes

This feature will show Wiki pages on openings even if the order of the moves changes. Basically, it looks for the Wikibooks Chess Opening page associated with the current position.


The commands feature is actually a combination of tools that register themselves with the cliCommands tool. This enables you to type / and then a command and execute various functions, besides the standard ones. Since commands are executed manually, they have no visible Preference to disable them.

Here is the list of available commands:

  • board - it will show/hide the board in Analysis mode (Analysis board and Studies). Use this with the Expanded move list and Hide left side options of the Move list options feature to have a move list filling the whole screen (good for presenting, for example).
  • trapvalue - provided the current move is in the Explorer database, this command will calculate the trap value of the current position. For more details on what that means, check out How To Calculate The Trappiest Chess Openings Using The Lichess API
  • copypgn ["fen"] ["separate"] ["tohere"] - this will copy the moves in the analysis move list (Analysis board and Studies) to the clipboard as the moves reaching the current position and any branching moves from it.
    • if fen is specified, the PGNs will start from the current position with the FEN tag specified
      • same as Shift-click on the Copy PGN menu item 
    • if separate is specified, each variation will be saved as a separate linear PGN
      • same as Ctrl-click on the Copy PGN menu item
    • if tohere is specified, the PGN only copies moves to the current position
      • same as Alt-click on the Copy PGN menu item
  • readgame [speed] [voice] [instrument] - this will read the game moves from the current position. It will follow only the first variation of every node, ignoring the others.
    • speed is an optional integer number, defaults to 100. Larger values makes the speech faster, lower makes it slower.
    • voice is an optional integer index number, defaults to 0. Changing it will change the voice which reads the moves, depending on your own browser setup.
    • instrument is an optional integer index number, defaults to 0. Changing it will enable a sound to be played in the background, based on the computer evaluation, if the game has been analyzed.
    • example: /readgame 80 2 1

Hide score tally crosstable

category: Play - Advanced
values: yes/no - defaults to no

Another user request was to not see the crosstable, the thing that shows how many games you played with the same opponent and what the results and games were. It was intimidating. This feature will blur it out, but allow you to click on it to unblur it. It's a silly feature that may not survive long because there is also the Zen mode lichess option which overlaps this behavior, but it's here for the moment.