Interactive Chess Whiteboard I am a coach at a small high school. We are starting a chess club. We have Epson BrightLink projectors with the interactive boards. Is there a way we can have a chess board displayed on the whiteboard that allows a finger to move pieces while also using a pen to annotate? An example can be seen here.

Try using the chessboard on https://szachydzieciom.pl/?page_id=61146 in full screen mode (click the full screen icon). I know that in some schools in Poland it works well with touch whiteboards. But dragging pieces may not work. Instead you should tap the piece to move and then disconnect your hand and tap the target square separately.


What is the origin of the Merida chess font? Currently the most popular chess font is Merida. I used to be under the impression that this was a new font from the computer era, but I found it in a German chess book from 1952 (Lasker's biography).

The question is about the origin of this font. When was it introduced and how widespread was its use in the precomputer era? Does anyone have old books with such diagrams?

The oldest reference I have for that chess typeface is to Linotype, so I suspect it may have been one of their foundry typefaces (i.e. created by their own artists, not by a 'well-known' type designer). The lack of detail suggests it may have been intended for a printing process that could not do fine details very well:  some of the earlier chess typefaces had very fine details, and required good paper as well as good printing technique for those details to be seen.  This typeface looks more as if it might have been intended for newspaper printing or similar 'fast' printing.

Adobe has it in their 'Linotype Game Pi Chess Draughts' font set, so I'm fairly certain it's a Linotype face.

Best way to find out more is probably to visit museums of printing, or type design, such as the Letterform Archive (who seem to have a large number of Linotype master drawings).  They are planning for online access -- it may possibly be found there when that comes on-line.


Why is Stockfish giving me this weird move? When I ask for the best move for this FEN:

  1rbq1rk1/b4p2/p2p3p/3Bp3/P3P3/2P4P/R2Q1PP1/4K2R w -- - 0 30

[FEN "1rbq1rk1/b4p2/p2p3p/3Bp3/P3P3/2P4P/R2Q1PP1/4K2R w - - 0 30"]

Stockfish (via Python) replies

  e1e2

which is a losing move, since there's a free pawn on the 6th rank that the white queen can take. Instead, Stockfish wants me to move the white king for some bizarre reason.

Why does it do this?

I suspect it may have something to do with the ending to the FEN, namely the part where it says

  -- - 0 30

I wrote the first part of the FEN by hand, and it is correct, but I didn't know what move it was or how to describe castling, so I just made up the "-- - 0 30" part. Is that the reason Stockfish gives this confusing answer?

You have a bug in your script. Try it on Stockfish yourself:

position fen 1rbq1rk1/b4p2/p2p3p/3Bp3/P3P3/2P4P/R2Q1PP1/4K2R w - - 0 1
go movetime 1000

  bestmove d2h6 ponder c8e6

How many nodes have you given Stockfish to think?


What should I play in this BvN endgame position? [Black "DrZ214"]
[fen "8/5p2/6k1/3KP3/6Np/8/8/b7 b - - 0 1"]

1... f5 2.Nh2 f4 3.e6 Kf6 4.Kd6 Be5 5.Kd7

Note: The board is from black's perspective. Black to move.

I was black and lost this endgame, starting with 1...f5. I thought it would be good to push the pawn and gain a tempo against his knight. I calculated that if he played en-passant (2.exf6), I would take his pawn with my bishop (2...Bxf6), 3. Nxf6 Kxf6, then his king would get up ahead of my pawn and it would be a draw.

He played 2.Nh2 instead, blocking my edge pawn. Then I played 2...f4 3. e6 Kf6 4. Kd6 Be5+ 5. Kd7, and I could tell I couldn't stop his pawn anymore. My darn bishop did not have enough room to get on a diagonal attacking e7.

Sorry I don't have full game record. We just take photos at the end of the game, and at interesting positions that we feel are pivotal, like this one.

So in hindsight, I could have tried a few other things like Kg5 or even Kf5, or else Bc3 to make some room for it. Even f6 might work? I feel like I should have at least been able to draw. Is there a winning move?

I tried entering this into some on-line tablebases, but it's a 7-piece endgame and they apparently aren't freely available.

The 7 man tablebase (for which there is a free android app) says that the position is won for black and it says it is mate in 21 moves (with perfect play from both sides) after 1... Kg5 which is the only winning move.

To me this seems like the most logical move in the position. There is no danger of the white pawn queening anytime soon and Kg5 will attack the knight which will be forced to retreat to h2 or f2 trying to stop the h pawn. Knights are particularly bad at preventing h/a file pawns from advancing as the knights can easily run out of space on the side of the board. And with the white king far away you should have good chances to achieve this. Note that 1... Kf5 or Kh5 which would also attack the knight are not immediately as attractive as they run into potential checks by the knight (in a real game you should still consider these options of course).

After 1... Kg5 2. Nh2 or Nf2, black plays 2....Kf5 which (i) blocks the white king from helping the knight, (ii) prevents white from playing e6, (iii) eventually wins the pawn on e5 (e.g. if white play 2. Nh2 Kf5 3. Nf3 h3 and black has the tactics of Bxe5, Nxe5, h2).

Your approach (1...f5) does not make much sense from a practical point of view. Either you are playing for a draw, in which you could easily force it by 1...Bxe5; and white does not have sufficient mating material. Or you play for a win, but then 1...f5 does not make sense either as white can (at least) capture the pawn en passant which will basically force you to exchange bishop for knight on f6 after which the white king is just in time to catch the h pawn (i.e. to reach the square h1). So it would be a poor winning attempt with added risk of losing. Generally if you want to win such endgames it is better to keep as many pawns on the board as possible. This is even more important in this example where you have the wrong bishop for the h-pawn: i.e. you could not win king + bishop + h-pawn against the bare king as long as the white king makes it to h1 in time.


Could I get in trouble for insulting an arbiter during a tournament round? Suppose that, during a round of an official FIDE-rated tournament, I insult the arbiter privately (they notice), without distracting any of the other players. Could I get expelled from the tournament or lose that game?

Incidentally I'm a national arbiter and a passionate player at the same time. Here is the rules side: FIDE rule 11.1 forbids the player to do anything bringing chess in miscredit. We have no yellow card (actually, I do have one in my arbiter kit, just in case :-) but insulting the arbiter definitely falls under 11.1 and is punishable by all the 12.9. sanctions (and yes, 12.9.9. allows to throw a player out of a tournament, but the punishment must fit the crime).
Now the big question is: why should a player insult me? 90% of all decisions are clearly governed by FIDE laws, I simply tell the player why law isn't on his side, and chess players may be wackos, but they are reasonable wackos. ;-)
A further 9% are lie-vs-lie situations (say piece touche and I didn't see it) where I have to make a decision on good faith. I communicate that too, the players will accept that too even if I factually wronged one. OK, assume that it's one of these situations where everything went south and the player calls me a frelling drenhead in the heat of the battle. Guess what, I think "so's your mum", a good arbiter should be able to handle such a situation with dignity. And as Brian suggested, it's very improbable he pulls out the nuke.
That said, in my player career (and I'm 60 and play around 50 tournament games in a normal year), I personally observed the following...
1 act of physical violence (to my best knowledge, the perpetrator got life - chess exclusion, that is),
1 act of justitiable name calling (the two are arch enemies and probably would kill each other if unattended; the called kept an ice cool, making the caller look like a complete idiot, he probably scored this as check mate),
zero incidences of insulting me either as player or arbiter.


Is it legal to use a chess database in correspondence chess? Someone told me that you can use a chess database for correspondence chess, but this seems a little like cheating. Does anyone has some information on this subject.

According to the official rules of the International Correspondence Chess Federation, you are allowed and encouraged to. It is regarded as learning an opening. Of course, there are different rules for some sites, but most sites follow the ICCF rules.


What does columns 1-24 mean? I was reading Modern Chess Openings by Nick de Firmian, and found "columns 1-24 deals with 2...exf4 " in relation to a theory table. So what does "columns 1-24" mean?

This table can be thought of as a tabular representation of an opening tree of in-theory moves where the rows (y-axis) represent the flow of the game and the columns (x-axis) refer to variations/branches in the tree that can occur.
The author in your quote indicated that 2...exf4 spans a family 24 variations/sub-variations that are noteworthy (and considered theory) for reference.
Here's an example for another such page on these NCO/MCO opening references.

If this is confusing,  let's consider a simpler example with the first few moves (with some early deviations) from the popular Danish Gambit.
Here's what a fragment of the opening tree would look like.

If I wanted to represent/transform this tree into a table, it would look like this.


Amazing chess feats while in altered states of consciousness This might seem an odd question, however out of personal curiousity, are there any documented accounts of amazing feats by players while in an altered state of consciousness?  What I'm looking for would be something like attempts at drunken, blind, simultaneous chess.

I don't know if this counts, but here is a story (unfortunately only in Norwegian) about the former president of the Norwegian Chess Federation, Jøran Aulin-Jansson, who in his youth played blitz for 92 hours straight: http://www.nrk.no/sport/92-timer-med-sjakk-i-strekk-1.6589371

In 92 hours and 26 minutes he played 701 games and won 549 with 32 draws.

He explains how accidentally eating a rotten chicken kept him awake during the third night.

At one point he hallucinated about spiders crawling up his leg. I guess that qualifies as "altered state of consciousness".


Modern defense Benoni setup with Ne7 I saw a DVD with GM Roman Dzindzichashvili, where he recommended, when white avoids the Dzindzi-Indian by playing 3. e4, that black adopt a Benoni setup but with the important difference of playing going Ne7 instead of Nf6.

[FEN "rnbqk1nr/pp3pbp/3p2p1/2pp4/2P1P3/5N1P/PP3PP1/RNBQKB1R w KQkq - 0 7"]
1. d4 g6 2. c4 Bg7 3. e4 c5 4. d5 d6
5. Nf3 e6 6. h3 exd5

White I find this this attractive when indeed black manages to take control of the central dark squares and then play Ne7-f5-d4, I find that white with exact play can make black's position quite uncomfortable. This is especially so when white does the following:
1. When white recaptures cxd5 instead of exd5 (in the exd5 case the white king is more exposed, giving black dynamic possibilities) when the f5 square is not as definitely under white's control, certainly so when the light squared bishop goes do d3. Roman recommends black playing for an f5 break in these positions, but seems to me to be super-risky.
2. Prevent Bg4 and thus Bxf3 by playing h3
3. Going for a quick Bf4 before black gets to play Nd7, pressurizing d6 and intending e4-e5.

My questions is: Is it possible to state in general terms that when plays cxd5 and h3 and a quick Bf4 --> play Nf6, otherwise play Ne7? Someone who has another take on this question?

Like all positions in chess, it's incredibly difficult to come up with general terms and common rules for openings. The particulars of each situation must be judged separately.

That being said, the idea that Dzindzichashvili is recommending is a good one - Ne7 stays flexible (and keeps your bishop open) and allows you to quickly strike at white's center with f5 (a crucial pawn break against d5-e5 structures). As you said, this pawn break can be double edged because you are creating a critical hole in your position: e6. So only consider it if there is no chance for white to sink a knight or bishop onto e6.

Now to respond to the line you are suggesting: I would argue that this plan still works in this line as well. Moreover, striking in the center while you are castled and your opponent is not seems principled as well.

[FEN ""]
1. d4 g6 2. c4 Bg7 3. e4 c5 4. d5 d6 5. Nf3 e6 6. h3 exd5 7. cxd5 Ne7 8. Nc3 (8. Bf4?? Bxb2) O-O 9. Bf4 f5!? 10. e5 dxe5 11. Bxe5 Nd7

I agree that you're still in a cramped position, and you obviously have to be careful about the d pawn pushing forward. But let's look at the dynamic positives here as well. The center has blown up and white still needs 2 moves to castle. You have a queenside majority that can instantly start pushing with a6-b5. And you have the ultimate blockader on d7 already setup. So there's no worries there. There are also interesting opportunities for f4 followed by Nf5. These are the types of explosive lines you are signing up for when you allow your center to gain a huge center as early as move 3.

Side note: If you truly want to trade off your light squared bishop, then your best bet is to play 5. Bg4 instead of e6.


Omitting piece letters in pgn Is it possible or common practice to omit piece letters (other than P) in PGN as long as the move is unambiguous?

E.g. h1xBh8

From what I understand from http://www.saremba.de/chessgml/standards/pgn/pgn-complete.htm#c8.2.3 it is not allowed. But then again, it's unambiguous. Has anybody ever seen a PGN game doing that?

It is not allowed by computer programs or by FIDE.

PGN is designed to be parsable by computer programs. Those computer programs depend on PGN files actually adhering to the specification. It would be similarly unambiguous if you numbered the ranks 9-16 instead of 1-8, but computer programs would not be able to read your game scores.

If you are not concerned about computers reading your moves and just want to save time writing on your scoresheet, you are still out of luck. The FIDE rules of chess say

  C. FIDE recognises for its own tournaments and matches only one system of notation, the Algebraic System, and recommends the use of this uniform chess notation also for chess literature and periodicals. Scoresheets using a notation system other than algebraic may not be used as evidence in cases where normally the scoresheet of a player is used for that purpose. An arbiter who observes that a player is using a notation system other than the algebraic should warn the player of this requirement.

and

  C.8 Each move of a piece is indicated by a) the abbreviation of the name of the piece in question and b) the square of arrival. There is no hyphen between a) and b). Examples: Be5, Nf3, Rd1.


In the Berlin Defence, why is 4.0-0 prefered to 4.Nc3? In the Berlin Defence, why is 4.0-0 preferred to 4.Nc3, as then White can transition into the four knights?

In a comment that ought to be an answer, @Ellie said: “The transposition from the Berlin Defense (1.e4 e5 2.Nf3 Nc6 3.Bb5 Nf6 4...) to the Four Knights Game (Spanish variation 4.Nc3) is a perfectly valid one, but the four knights game is known to be a quite dry opening for white, as in there are various easily equalizing lines for black, starting from the Rubinstein 4...Nd4 (see Kramnik games). Instead 4.O-O is the more critical line (one that offers more hanging fruits...) alongside the 4.d3 line which is known as an anti-Berlin approach.”


How does his 3 step plan by Petrosian works? [FEN "r6k/3q2bp/1p6/2pPp1p1/2P1QpP1/5P2/1P2R2P/2B3K1 w - - 0 1"]

Here Petrosian gives the following 3 step winning plan:
Stage 1: Tie down the black pieces to defense of the e pawn: 13.Bd2 Re8 14.Bc3 Qd6 15.Re1
Stage 2: Switch to the a file: 15..h6 Ra1 and then Ra7
Stage 3: Penetrate into the white squares.
Now what I don't understand is this: when he proceeds with stage 2 by bringing the rook to a file, isn't he removing one attacker of the e pawn? Now black's pieces will not be tied to the e pawn anymore. So, how is this plan any effective?

when he proceeds with stage 2 by bringing the rook to a file, isn't he
removing one attacker of the e pawn? Now black's pieces will not be
tied to the e pawn anymore. So, how is this plan any effective?

Currently black controls the a file with the rook on a8. The whole point of step 1. "tie down black pieces defending e pawn" is to force the a8 rook to give up the a file to defend the e pawn with Re8. Only when that is accomplished can white take over the a file with Ra1. The whole point of having a multi step is achieving the last step. The earlier steps are only necessary because without them the last step cannot be forced.


Lichess puzzle 87510: How much calculation would a strong player do before playing Bg4+ when white has a range of (all losing) responses? Lichess puzzle 87510 has this position.
[FEN "r1b1k3/pp4R1/2q3RQ/4p3/5P2/bP2P3/2P1K2P/8 b - - 0 1"]

The solution is 1...Bg4+,.after which White has 6 legal moves:

1...Bg4+ 2. Rxg4 Qxh6, which is the computer solution, possibly followed by 3. Rg8+ Bf8,

Kd3, which is mate in 7,

Kd2, which is mate in 8,

Ke1, which is mate in 5,

Kf1, which is mate in 4, and

Kf2, which is mate in 4.

I feel like a human player in a tournament would not calculate the whole decision tree, and probably just intuit that 1...Bg4+ is going to win since black can continue with a range of powerful moves Qf3, Qc2, Rd8, and Bb4 and at least one of them is with check, depending onWhite's response.
Question: How much calculation would a strong player (say an FM+) perform before playing 1...Bg4+?
It's a dangerous movem Black begins with an exposed king, with mate threats and a possible rook skewer, and queen attacked, and Black responds by creating an undefended bishop.  If the checks ended, Back would probably lose.

I'm an FM, and my calculation process would be as follows:

1) See that after 2.Rxg4 Qxh6 2.Rg8 Bf8, I'm clearly winning and White has no follow up.

2) Look at White's king moves to get out of check. Immediately Kd1, Kd2, Kd3 can be discarded since they just let me play ...Rd8+ for free. Also, Kf1/Kf2 lead to the same thing after I play 2...Qf3+. So I'd just look at Ke1 and Kf2.

3) Everything looks good, so I'm done.

If I were in time trouble, I'd play 1...Bg4+ seconds after seeing it. Since 2.Rxg4 doesn't work, there's no practical risk to playing it.


Software for reading multiple FEN positions I have started playing around with SCID and Arena to analyze my games and store interesting screenshots. I recently heard about the FEN notation which makes it conveninient to describe chess positions (previosuly I used to store screenshots of the board positions)
Now I know that SCID can read a single FEN string and set up the described position from that string but as far as I understand, it cannot read a file containing multiple FEN positions, and iterate through them.
What I would like to do is keep a database text file with interesting positions from my games or famous games or typical opening positions into a single file, one FEN string per line along with a short comment giving some more context and information about the position.
So the file  would be something like
1b6/4pKn1/8/1nPkqp1R/2pr3p/3b1pp1/P3Qp2/2BRr3     # comment 1
1B6/4pKR1/3b3p/3QN2p/1Rb2k2/3PpN1P/2q1P3/8        # comment 2
1b6/4pN1K/2qpQ1p1/R4n1p/1Prkb3/N2p1pB1/3P1n1r/8   # comment 3
1B6/4pN1p/7p/3P1k2/2p5/4P2K/4P3/2Q4N              # comment 4

Is there some analogous file format to do this? Maybe PGN itself is good enough? Can SCID handle such a file with multiple FEN notations? Or is there some other software for reading such files and allowing me to iterate through the various positions described in that file (and hopefully allowing me to make some edits)

A file that contains one FEN per line is a file format in itself. It's the file format used by test positions for chess engines. So engines definitely have some process to analyse all the positions in a FEN file.
(Ermm... your FEN is missing the king-castling, move number and who is to move indicator -- you'll want those.)
An alternative would be to convert each FEN line into a PGN game -- The FEN line goes in the PGN header, e.g. [FEN "1b6/4pKn1/8/1nPkqp1R/2pr3p/3b1pp1/P3Qp2/2BRr3"], and the comment can just be a "Before move annotation". So you could construct a minimal PGN game for each position -- and PGN is supported by absolutely every single piece of chess software out there. There is a minimal set of headers required for a valid PGN game, White, Black, Site, and Result. Plus that FEN header.
Scout around, maybe you can find a fen2pgn script. There was one a few decades ago.


Can it be said that draws occur less often between top-level players of equal caliber, rather than machine draws? We would be considering, of course, the over the board rating of the respective machines and/or players.  I'm ultimately wanting to see evidence that suggests there is an increase of draws amongst machines with modern technology paired against one another, over humans paired with similar ratings.  For example, if we compared games with both players at 2700 strength, would they have a higher draw rate than the best machines, when paired off opposing one another?

I know that this tends to happen when considering humans alone.  Does the trend extend, ratings wise anyway, beyond human playing strength?

The draws among chess-playing machines tend to be far more than players of 2700-plus Elo Level. Of 100 games, and I mean in 100 matches, machines will have 60-70 draws compared to humans where they may have 50 draws.

Now the score can fluctuate a lot from the players side owing to different conditions .

Both players are not in a Spirit/mood for fighting as like Kasparov/Karpov 1985 WCC.
Unlike a computer, a strong 2800 player may not be in his best form. He may have different reasons like health/family problems, or other factors which may cause a setback .
A Player may even make a basic tactical mistake and lose the game like Anand did against Carlsen in 2014 WCC match.

These are some reasons that a machine does not encounter at all, and plays freely. You can even check the database among players, and if possible there is a lot fo history associated with famous chess games. You could find many interesting stories which would adjudge many of the reasons above and even attract various other info.


How do I host a casual tournament for elementary level players? I am a chess instructor teaching a summer camp class of 20-ish kids at the 2nd-6th grade.

I want to hold a tournament on the last day of the camp. Any ideas on how to carry this out are appreciated. Here are my concerns:

The session is only 2 hours long. Therefore I can arrange between 5 and 6 rounds, max.
I don't want to have an elimination style because I want everyone to feel like their games still matter towards the end.
I don't have the kids' ratings but I do have them seeded based on observing their play for the last three weeks.
I anticipate most of the games ending in a draw, therefore I would like to incorporate points (captured material) as a method for tie breaking.

Thanks in advance.

(I work for an after school chess program... I've run 100ish end-of-session tournaments for K-6 kids).

Not sure why you anticipate so many draws... I see maybe 95% checkmates, 4% stalemates and the occasional insufficient material or "failure to make progress" (TD discretion in lieu of 50-move rule).

My goal is to keep kids playing: finished games get new pairings as soon as opponents are available. I don't use clocks, might for older kids if I had them available. I don't track losses. I don't allow resignations. I do track the order they arrive at a given checkmate total. So if I have two kids with three checkmates the one who got to three first prevails.

Yes, there's inherent unfairness in this format. Speed matters. Getting in a tight, slow game can be fatal to kids who should've been contenders. Less offensive to me than having a bunch of kids in an extended wait for the next round. I only have an hour, I really need to be efficient.

I LOATHE piece-value based scoring. I had to do it a couple of times when I was an assistant and it wasn't my decision. It's kind of the only option if you've got kids that can't get checkmates though. But even K/1 groups, if you don't have at least half capable of winning a game after 8 sessions their instructor is a problem.

I don't do a lot of seeding, but I try to keep the contenders away from each other on the initial pairings.


Uploading chessboard to website I am a beginner programmer with some experience in HTML, PHP, and Java. I would like to upload a chessboard onto my website, and I have used the following links to help me:

http://chess.geniusprophecy.com/chess-viewer.html

http://chesstuff.blogspot.com/2008/11/chess-viewer-deluxe.html

However, I am getting stuck in placing the code (in steps 2. and 3. of the second link) in my source code. For example, what lines should I change and manipulate in

<APPLET archive="Viewer-Deluxe.jar" code="ChessBoard.class"
codebase="/bin" width="631" height="560" mayscript="true">
<PARAM name=PgnGameFile value="/games/Samples.Pgn">
<PARAM name=LightSquares value=F3DCC2>
<PARAM name=DarkSquares value=DDA37B>
<PARAM name=Background value=CCCCCC>
<PARAM name=ImagesFolder value=images>
<PARAM name=PuzzleMode value="off">
Your browser is completely ignoring the &lt;APPLET&gt; tag!
</APPLET>

in order for my code to work?
I've tried modifying the value="" line many many times and I'm frustrated because nothing seems to be working. I've saved my files in the right directory, subdirectory, etc. but I keep getting the error

java.io.FileNotFoundException

I'm not too familiar with the Java applets that you're looking at, but I recommend that you use JavaScript for this sort of job. This GitHub repository can be used to display and play through your own games (it supports PGN and FEN).

There are many other libraries out there - it's easy for you to change the design of the board and pieces to suit your site's style. You also might want to ask this question on StackOverflow as you might find some more technical advice there.


Who was the last Indian player to beat Vishy, and when? The question came to mind following today's game between Vishy (Viswanathan Anand) and the young Raunak Sadhwani at the Isle of Man 2018 Tournament. Has Vishy been beaten by an Indian player since, say, the mid-90s?

The answer is: Yes

Krishnan Sasikiran vs Viswanathan Anand
FIDE World Cup-C (2002), Hyderabad, rd 2, Oct-05
King's Indian Attack: Yugoslav Variation (A07)
1-0

http://www.chessgames.com/perl/chessgame?gid=1357060


Does playing too much hyperblitz and bullet ruin your classical performance? Because of quarantine I haven't been able to meet up with my friends to play OTB games or go anywhere including tournaments to play OTB for that matter, so for the past year I have been playing purely online chess with my friends and randoms. When I play online I only ever play games faster than 3+0 because I hate sitting down and staring at the screen for too long, just not the same as staring at a board.
I got a lot better since last year going from 1700 rated online in blitz to 2000 rated. My friend who is around 2300 rated says that it's gonna make me play trash in tournaments and not good for my game, is it true?
I know I make one move blunders and mistakes often in this time format but I quickly realize a second after I made the move or sometimes as soon as I make it. So my logic is if it was a classical game I would spend at least 10 extra seconds looking over and I'd see the obvious blunder.
Has there been significant evidence or reason to believe that speed chess will make you a worse regular chess player overall? Or is it purely anecdotal?

Usually, when playing speed chess our eyes get trained to find tactics quickly, and we tend to overlook complex ones. Also, repeatedly playing speed chess over a significant time reduces your stamina which is needed for long games.
In my experience, when I spend too much with speed chess before a tournament, after I analyze my games I see that my games are not as technically sound as it used to be.
It is a bummer for me because love bullet chess :(.


Stockfish: How to do so it only gives hints to one color When using Stockfish it gives options/hints for both white and black. How do I make it so it only shows hints of moves for black? I am using mac.

I assume you want this so that you can train against the engine by playing the suggestion for black and then thinking about what to play as white?

Lichess allows this on their website. Set up a position in the board editor or analysis board, then pick "Practice against computer". If you like, it will even evaluate your moves as you go, telling you if you made a mistake, blunder, a good move but not the strongest move etc.

I often do this because too often I reach a winning position and then go on to squander my advantage. I go back to the winning position and see how to actually convert it.


How to add arbitrary move to analyze by chess engine in Arena I'm using Arena 3.5.1 with Stockfish_8_x64 engine. In engine output window it proposes best moves with different continuation variants and values. Can I add few arbitrary moves there myself and ask engine to calculate it values?

No. By definition an output window is for output from the program. You can only use input methods to input data. To do this just make the move you want on the board and see the computer analysis for that move in the output window. To do this for several different alternative moves create separate variations, one for each of your alternatives.


Reasonable engines to test against (Not StockFish) I've built a chess engine in Python which I've been testing against StockFish through the use of the Python-Chess package.

Testing against StockFish seems/is problematic, and as a result I'm looking for suggestions of engines to test against.

There are two major issues with testing against StockFish (the first much more significant than the next)

StockFish is partially used in generating the training data for the engine's evaluation function.
StockFish is extremely good, and even given extremely little time will perform well.  This makes it difficult to see the changes in the engine's strategy which resulted from a change in the engine's code

The engines I'm hoping to play against need to have no serious bugs or problems, and ideally would play at levels similar or a bit below a human master, without spending too much time running them.  UCI engines are prefered so that my engine can easily communicate with them through the Python-Chess API (note that this doesn't mean my engine supports UCI).

If it helps anyone to have some context, my engine is Batch First.

Since your engine supports UCI, I would suggest checking out lichess.org. You can make a BOT account there and test against several other BOTs and people as well! Also, you can get your BOT rated in different time formats!!

I must warn you that most of the BOTs on lichess some version of StockFish or other strong engine but you can find ample other BOTs.

Among strong BOTs (apart from Stockfish ones), I would suggest checking out:

LeelaChess: A neural net based BOT.
ASMFish

There are many more BOTs on lichess, you can view them here on lichess BOT team.

You can also find many not so strong self-implemented engines that you might like testing against, for example this.


Recommended mobile app or website to memorize openings? I'm looking to improve my game's opening.
Just wondering if any of you could recommend an app or website dedicated for this?

Chess PGN Master and pgnmentor.com are how I study openings. Download one of the large PGN files on the opening you want to learn, open it up with the viewer and autoplay through games during your downtime. I tend to stick to the games of only the players I recognize so that I am not learning from 1300s (there are a ton of high-level games in each file). This is great for learning the common themes of an opening. You don't have to understand every move but sometimes I will pause it and try to work out a particular tactic.

To memorize specific lines, I make openings files in Chessbase built from the games of today's top players (I consider anything that a 2600+ FIDE has played and my computer doesn't immediately hate to be playable for me). I then play through them, forcing myself to remember the options available for each side in the position before I make the next move.

As others have mentioned, focusing on openings is not going to help you improve very much below maybe 2000 FIDE. However, the first method I described can be used to improve at any level-you can retrieve all of the games of a great player (I started with Capablanca) and watch their moves zip past. This in my opinion is the best way to learn pawn structures. Jeremy Silman has recommended this method (though not this specific configuration) many times in his chess.com articles.


How should I read chess books that show games or parts of games? When reading books like Sorcerer's Apprentice or Life & Games of Mikhail Tal, often a position is shown followed by a list of moves, then another key position, then more moves, and another position, and some reasoning.

How should I read this part?

Should I set up the position on a board or on my PC or just try to imagine it in my mind? After reading through the moves I often feel like I haven't gained any knowledge.

It depends on what you want to get out of the book.

If you're reading for enjoyment, read the text, try to see the point behind the nice sacrifices, and relax.

But for study, you need to do something else: set up the position on a board, put the book away, then try to understand the position on your own. What are important features of the position? What is each side trying to achieve? Are there any tactics or threats? What's the best move?

Then play through the moves in the book. Try to understand them, how do they related to what you thought each side was trying to achieve? What was it you missed? Why are these moves best?

Basically, for study, treat every diagram you ever see as an exercise. The improvement in your chess skill will be directly proportional to the amount of work you put in.

Of course one doesn't always feel like doing that, and that is fine too (I love just browsing chess books). Just don't expect much real improvement then.


How to write a swiss pairing software I'm thinking about to develop an online service to provide free software for helping chess tournaments organizers with pairing systems like swiss, round robin, team-swiss, team-round robin.

Could you, please, send me some learning materials how those pairing systems work?

You should start with the section of the FIDE web site which describes the Swiss Rules. This has sections giving detailed descriptions of the different systems for making the pairings along with much other useful information.

It is also worth looking at the FIDE Tournament Rules which includes tables for round robin tournaments and descriptions of tie break methods which it is good to also have in a pairing program.


What is the longest wait before a draw offer is accepted? If I understand correctly, once player A makes a draw offer, the opponent player B retains the right to accept the draw offer as long as player B does not rejected it verbally, or touch a piece with the intention of moving or capturing it. So technically player B may spend as much time as he has left on the clock, say 60 minutes, before accepting the draw offer and once the draw offer is made, player A is not allowed to withdraw it.

So what is the longest record of waiting time before a draw offer is accepted?

There are no records of that.  We can possibly  tell of some long ones we heard of but the question cannot be answered for THE LONGEST wait.


Mismatch between my puzzle rating and game rating on chess.com On Chess.com, I recently passed 2000 in the puzzle section. However, in 10 minute games, I can't reach 1600. How do I bridge that gap and increase my game score? Is 10 minutes maybe too short of a game to find/apply tactics? I have some theory/strategy knowledge that usually gives me an edge (or at least an equal game) after the opening moves.

Rating method.
On chess.com, my puzzle rating is 700 points higher than my game rating, but my chesstempo puzzle rating is only about 100 points higher than my chess.com game rating. In other words, puzzle rating on chess.com is not comparable with your game rating.
I'd suggest just keep doing 10 (or more) puzzles a day and ignore whatever the gap.


Why was 3...c5 for black was a bad move? I played a player ranked about 450 points higher, and I was out-played. I managed to give a fight but was trailing all along.

The player used the English opening and on third move I (black) played c5. My aim was to control centre, and dissuade white from playing d4.

So ,I thought it was a good move, but upon doing analysis with computer it calls it an inaccuracy. Can anyone share why it is an inaccuracy, i.e. why is it a bad move?

[FEN ""]
1. c4 b6 2. Nc3 Bb7 3. e3 c5 4. Qc2 e6 5. Nf3 h6 6. b3 f5 7. Bb2 Nf6 8. O-O-O d6
9. d4 Nbd7 10. Nh4 g5 11. Ng6 Rg8 12. Nxf8 Rxf8 13. f3 g4 14. Nb5 Nb8 15. dxc5
d5 16. Nd6+ Ke7 17. Nxb7 Qc7 18. c6 Nxc6 19. Ba3+ Kf7 20. Bxf8 Kxf8 21. cxd5
Nxd5 22. Bb5 Nxe3 23. Qxc6 Qxc6+ 24. Bxc6 Nxd1 25. Rxd1 Rc8 26. Rd8+ Rxd8 27.
Nxd8 Ke7 28. Nb7 h5 29. Kd2 Kf6 30. f4 e5 31. Ke3 e4 32. Be8 h4 33. g3 hxg3 34.
hxg3 Ke7 35. Bg6 Kf6 36. Bh7 Ke6 37. Bxf5+ Kxf5 38. Nd6+ Ke6 39. Nc8 Kd5 40.
Nxa7 Kc5 41. a3 b5 {

Game may have continued...} (41... b5
42. Kxe4 Kd6 43. Nxb5+ Ke7 44. f5 Kd8 45. a4 {+25.6}) 1-0

IMO, 3...c5 by itself, is not really a problem, after the strongest continuation  4.d4 stockfish gives 0.5, and after 4th move in the game stockfish gives equality. And I think your reasoning is fine, it is generally good to trade a c-pawn for d-pawn.

But it looks like it is a part of bigger problem: You made too many pawn moves 5...h6 And 6...f5, and later 8..d6, while not developing your pieces and getting your king to safety. Also by making these pawn moves you created weaknesses, for example your opponent was able to exploit weakness on g6.

Make sure that you focus on developing your pieces and getting your king to safety, and avoid making unnecessary pawn moves.


Why is Ng5 a draw here? Was shared a chess position and reached this position. I didn't understand why Ng5 is a draw. I analyzed h6 and h5 as responses but they fall to the same checkmating theme of rook checkmate on h8. More precisely... Bxh5... Bf2... Rg8... Rg5... Rg4... Rgh4... and threaten checkmate.
1r3rk1/5p1p/1qb1pPp1/3pP3/p1pP4/PpP2N1R/1Pn1B2P/3RB2K w - - 1 3

Can someone enlighten me on why Ng5 isn't winning?

When I feed the position to Stockfish (12), it's first impression (depth<20) is that it is won for Black (evaluation at around -8.0). But that's probably just counting material.
After some calculation, the evaluation changes to 0.0 - for four different first moves by Black: 1...h6, 1...h5, 1...Nxa3 and 1...Ne3 (still holds at depth 43).
That's probably enough options to claim that White cannot bust them all and win.

Example analysis of 1. Ng5 h5 2. Bxh5 Nxa3 (0.0 by Stockfish at depth 41)

2...gxh5 3.Bf2 with mate in 6.

3. bxa3 b2 4. Rb1 gxh5 5. Rxh5 Qb3 6. Rh7 Qc2 7. Rg7+ Kh8 8. Rh7 Qxh7** -+.

The sacrifice 3. Bxg6 fxg6 is harmless, Black can bring in defenders via the opened 7th rank.

After 3. Bg4 or 3. Bf3 or 3.Be2, it's a draw, e.g. 3. Bf3 Nc2 4. Bd2 a3 7. Rg1 axb2 and White is one move short. 8. Rg4 b1=Q+ 2. Kg2 Ne1+ loses, the queen either goes to e1 or to f5 and takes one rook.

However, White seems to actually gain a small advantage by 3.Bd2 Nb5 4.Rg1 Qa7 5.Rg4 Nd6 6.Nxf7 Qxf7 7.Bxg6 Qxg6 8.Rxg6+ Kf7 9.Rg7+ Ke8 10.exd6 with +1.0 ~ +2.0.

Never mind, 3. Bf2 wins for White (because he can later shield his king by Bg1, allowing the king to stay out of reach of the Nc2 and thus gain that critical one tempo he needs to mate). Neat.

The same idea applies in the 1...Nxa3 variation: 2. Rxh7 Nc2 3. Bf2! a3 4. Rg1 axb2 5. Rg7+ Kh8 6. Rg3 b1=Q+ 7. Bg1 and Black can't stop the mate.

Well, it looks like the position is won for White after all, the engine just can't see it from the beginning.
Why it can't is a different question - that is already answered in length elsewhere on this site. In this instance, I guess the constant option of perpetual check combined with the serious material disadvantage completely throws off the pruning mechanism.


Doubt about best move in lichess.org training puzzle In this puzzle, https://lichess.org/training/61639, in this position:

1k2n1rr/1b4q1/1p1p1p2/1PpPpQ2/2P1PnN1/2N4P/R5PK/R2B4 b - - 10 33

the engine says that the best move for black is Rh5, I think it should be Bc8.

No. After ...Bc8??, Ra8+ checks win for white.


What are some "quick start" openings? First of all, I'm sorry if it looks like I didn't really research before asking the question, but I really did put in some effort and couldn't find a satisfying answer.
My problem is, I don't want to spend a lot of time studying openings. I don't really like the early game that much, I really just prefer to get it over with. I don't want to waste time learning a lot of theory by heart, as I'm relatively new, and I believe the biggest improvment will come from actually playing the game and not memorizing moves. Another problem is, when I'm trying to "just play", react to what the enemy does without going by any theory, I usually end up wasting tons of time against someone who knows what they're doing in their opening.
So, the question is - what are some easy, "quick-start" openings which don't require you to learn 12 different variations, which are relatively safe and prevent some early game cheese tactics that would confuse a begginer? Is there such a thing? I'm interested in both white and black openings.
Currently I am spamming the King's Indian Defense in 99% of my games, and I do enjoy it, however I'd just like to try something different, maybe something that fights for the centre a little bit more in the beggining?
They don't necesarily have to be setup openings (as in, an opening that's almost independent of what the oponent does), maybe a theory based opening that's pretty "universal" or, well, "easy" to learn?

The path to mastering the openings isn't memorising moves and variations, it's understanding why certain moves are played in specific positions, why certain moves are favoured over others.
Memorisation is a shortcut to understanding, not a replacement. There are sharp offshoots of most opening systems that mean you have to be aware of certain traps and tactics, whether that be through understanding the position, memorising the move that avoids the trap, or calculating the tactics of each position.
System-based openings are less memory intensive, for example, the King's Indian Attack as White. There are certain theory lines that require some blend of memorisation/understanding/calculation, but most of the times the opening plays itself into a fairly standard set of middle-game positions.
The basics of openings is to occupy the centre, develop pieces towards that end. The next step of openings is to control the centre (not occupy), and develop pieces to either control the centre, or reduce your opponent's control of the centre (e.g. pins, exchanges, forced retreats). The King's Indian Defence is one of the latter sets of openings, of controlling the centre, not of occupying it, it is designed to let White dictate what centre he wants, and then for Black to undermine it. You want something more immediate, so you're looking for openings based on the classical view of the centre.
If you're looking for openings that more directly occupy the centre, then the Queen's Gambit Declined (or it's Slav relatives) is the most classical of openings to occupy the centre.
Basically meeting 1.e4 with 1... e5, and 1. d4 with 1... d5 will give you Black's best approach to occupy the centre directly, and directly contest White's attempt to occupy the centre.
I'd advise sticking to mainlines of major opening systems. They are mainline because they've been tested many times at highest levels and retain their soundness.


What is the difference between a brilliant move and the best move? As far as I know, nowadays the chess engines can judge that a move is the best or that it is brilliant (usually denoted by ! or !!). I was wondering what is the precise criterion for this classification.
I was reading some forums and stepped on this discussion. There, some people claim that a brilliant move is one that the engine does not find and, a posteriori, finds it to be brilliant. Some other people claim that a move is marked as brilliant only if the player continues the game responding with the absolute best moves, for some number of moves ahead. Finally, there is also the opinion that a brilliant move simply cannot be reached by the engine up to a certain depth, which is what I would instinctively think too. Thus, this would imply that if the engine performed a sufficiently large-depth analysis then there would not any be brilliant move markers. Is this correct?
Finally, my question: What is (if it even exists) the specific criterion, based on which a chess engine marks ones move as brilliant, rather than simply the best.

Just my opinion.
The best move is the one with the best evaluation, with the exception of the "computer moves" which only delay the real threat for a move.
A brilliant move is not only good but has a surprise value.  A correct sacrifice easily qualifies, but a move with an unusual (and correct plan do tend to be brilliant.  There are two examples:  a computer played Re1 in it's match against Kramnik with the plan to get the rook to g3 and a game (I think) by Fischer where he played a4 followed by Ra1-a3-b3 just to make black slightly more passive by having to defend the b6 pawn.  (Normally every contributor would try to find these examples, but. right now, I don't have the energy.)
BTW, this question is really a matter of opinion and shouldn't be asked.  When/If this question gets closed, try to learn from the experience.


Is Chess960 a desirable alternative to classical chess? Considering the great depth to which most opening lines have been analyzed by computers now, requiring a voluminous memory to compete successfully at the highest levels, is substituting the variant Chess 960(Fischerandom) for classical chess a desirable option to revitalize the game and restore the creativity that was once its hallmark?

I want to put forth a few arguments, why I don't consider it desirable to substitute classical chess with Chess960:

The rumours of a draw death of chess have been greatly exaggerated. The idea that chess will one day be played out, is more than a hundred years old, but the draw rate in top level chess is actually growing very slowly. And the rate of short draws has decreased a lot in the last decade because of Sofia rules and similar measures.
The idea of the draw death and of Chess960 is that opening theory will become the dominating factor in top level games, but in recent years it has been pretty obvious that the opposite is actually happening. Nowadays you cannot really regularly outprepare your opponents anymore. Players like Carlsen don't even try to get opening advantages, they just go for an unknown position and play chess. In the end, when everything is known about openings, preparation will probably play less of a role, not more!
Openings are an integral part of how chess is played. Openings are rather like genres in literature, they have their own character and this adds depth to the games. Many players like "their" openings. I wouldn't be any happier about never playing or replaying a king's gambit game anymore than I would be about never reading an epic fantasy novel again. If you throw opening theory out of the window, you also get rid of a lot of knowledge and history. In the end you have games that are played on a lower level and aren't part of an intricate and well understood history of games in a particular variation.

Conclusion: Chess960 is a fun alternative, but substituting classical chess with Chess960 would probably be more of a loss than a gain.


What should the arbiter and what should have I done in this case? Recently, an official (FIDE-rated) tournament was held, where I participated.
In the last round – which was the most critical one – I was black and my opponent white. In the middle of the game, they started making strange sounds, which clearly disturbed both the nearby boards and me.
At first, I mentioned that they were disturbing. Since they wouldn't listen, I called the arbiter. In all 4 cases, the arbiter warned the user like this:

<Player name>, could you please stop doing this, since you are disturbing your opponent?

In addition, when I offered draw, here's what my opponent replied:

If the game were drawn, then I would offer it first to you.

What should the arbiter have done? At least, I'd expect to have a punishment in the clock (e.g., +2 minutes for me, -2 for them). It is well-defined in article 11 of Fide Laws of Chess (emphasis mine):

11.5 It is forbidden to distract or annoy the opponent in any manner whatsoever. This includes unreasonable claims, unreasonable offers of a draw, or the introduction of a source of noise into the playing area.
11.6 Infraction of any part of Articles 11.1 – 11.5 shall lead to penalties in accordance with Article 12.9.
11.7 Persistent refusal by a player to comply with the Laws of Chess shall be penalised by loss of the game. The arbiter shall decide the score of the opponent.

And I suppose that this behaviour is persistent.

What should I have done? I ended up losing the game and, while I could end being 2nd, I ended up being 3rd! Could I make an appeal to another arbiter or even the chief?

First, we cannot tell you what the arbiter should have done because we were not there and certainly don't have all the facts. We only have your version of events. What you say was very disturbing may not have been perceived as so disturbing to others there at the time. We weren't there, so we just don't know. We can't judge.

As to what you should have done, you did the right thing by bringing the disturbance you suffered to the attention of the arbiter. If the arbiter took no action beyond issuing a warning you could have made another appeal to the arbiter during the game for more robust action.

At the end of the game you could also have refused to sign the scoresheet and instead raised the issue again first with the arbiter and then the chief arbiter. If this failed then you could have lodged an appeal with the appeals committee for the tournament. FIDE rated tournaments are required to have an appeals committee to which you can appeal during the tournament. This committee is usually composed of players in the tournament and disbands when the tournament finishes.

Finally, if you took all those actions and still did not get a satisfactory answer you could appeal to your national chess federation. You could probably still do that now but if you didn't make the previous levels of appeal and complaint you are unlikely to get any satisfaction.

Currently there is a high level women's tournament (candidates for world championship) taking place in Kazan in Russia which has a problem with noise from a band playing music outside. Some of the players have earplugs and are not being disturbed by it others do not and are being disturbed.


List possible moves for player - Haskell implementation I'm trying to implement a function in Haskell that returns a list containing all possible moves for the player who's up. The function's only argument is a String composed of an actual state of the board (in Forsyth-Edwards Notation) followed by the moving player(b/w).
Notation example : rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w (starting board state)
So far I used a function to split the string into ranks, but I'm having a hard time coming up with an implementation.
Any tips?

FEN is fine for unambiguous communication of a position (if you include castling and e.p. state too) but the internal representation should be as a board, with some kind of movement so you can efficiently check for legal moves, blocks, checks etc. Would hate to do all that with regex!
This quite a well-travelled area, and there must be much material online. You have made the choice to use Haskell here: what is the motivation for this? Are you trying to learn Haskell, or do you think it’s appropriate for certain aspects of a chess engine.
Chess is a finite directed binary graph, with each position just a node. There is certain machinery to reach that level of abstraction, but ultimately I would think a functional language like Haskell might really begin to show its worth when you have reached that conceptual level.
Depends also what you want your engine to do: find good moves, solve problems, analyse endgames, tablebases, retrograde analysis, support fairy chess. So please say more! :)


Franci de Castellvi - Narcis Vinyoles 18. ... Qg6??, a blunder by black? [Site "Valencia"]
 [Date "1475"]
 [White "Franci de Castellvi"]
 [Black "Narcis Vinyoles"]
 [Result "1-0"]
 [startply "36"]
 [FEN ""]

 1. e4 d5 2. exd5 Qxd5 3. Nc3 Qd8 4. Bc4 Nf6 5. Nf3 Bg4 6. h3 Bxf3 7. Qxf3 e6 8. Qxb7 Nbd7 9. Nb5 Rc8 10. Nxa7 Nb6 11. Nxc8 Nxc8 12. d4 Nd6 13. Bb5+ Nxb5 14. Qxb5+ Nd7 15. d5 exd5 16. Be3 Bd6 17. Rd1 Qf6 18. Rxd5 Qg6?? 19. Bf4 Bxf4 20. Qxd7+ Kf8 21. Qd8# 1-0

A notable game in chess history is Scachs d'amor, recording a game of chess in the 15th century close to the current rules of the game. It does so in the form of a poem (original text, English translation).

Most of the game shows reasonable play, if not exactly modern. But when it comes to this move, it simply seems pointless. Consider for example the alternative 18. ... c3, which ultimately wins back some lost material for black, possibly giving better chances to secure a draw.

In any case, Castellvi quickly takes advantage of this, mating a handful of moves later.

What motivates 18 ... Qg6??

Some speculation:

Is it some (misguided) attempt at an offence by black, and in that case, what could Vinyoles have tried to achieve? Or is there some subtle difference from the modern rules, leaving this an acceptable move?
The game is somewhat artificial, acting as a tutorial for the rules of the game. Is this move necessary to show of an important rule to the reader?
Maybe it is for some kind of artistic purpose? The poem follows a strict form, and is divided in 64 stanzas. Does this awkward move somehow help achieving this form? Or does a formulation like "Queen’s check mate in the house of the other Queen" add something of value by allegory?

These players are just pretty weak. 5...Bg4 should already have been punished by Bxf7, many more blunders follow.

Qg6 is a double attack against c2 and g2, that's probably motivation enough.


Obtain information about a a position from Stockfish I want to know from Stockfish:

All possible moves in a position, a.k.a. a depth 1 analysis with no score.
If the king is in check, is checkmated, or if there is a draw.
The current FEN string, after a move.

How can I get all of those? I tried looking in the UCI specs and there is nothing like it.  I found some answers as to the first question, but they were all in Python. I am looking for pure UCI commands as I am using C#

If you do not want to use a library/API to get this information, then you will need to implement some parsing to get it, but in principle (almost) all the info you need is available via (non-standard) UCI commands:

Legal moves

Perft lists all legal moves. E.g., for the starting position go perft 1 gives you:
a2a3: 1
b2b3: 1
c2c3: 1
d2d3: 1
e2e3: 1
f2f3: 1
g2g3: 1
h2h3: 1
a2a4: 1
b2b4: 1
c2c4: 1
d2d4: 1
e2e4: 1
f2f4: 1
g2g4: 1
h2h4: 1
b1a3: 1
b1c3: 1
g1f3: 1
g1h3: 1

Nodes searched: 20

2.+3. Game state
d is a non-standard UCI command in Stockfish to print debug information. It contains information like the FEN and pieces giving check, e.g.,
position startpos moves e2e3 f7f5 d1h5
d

 +---+---+---+---+---+---+---+---+
 | r | n | b | q | k | b | n | r | 8
 +---+---+---+---+---+---+---+---+
 | p | p | p | p | p |   | p | p | 7
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   | 6
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   | p |   | Q | 5
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   | 4
 +---+---+---+---+---+---+---+---+
 |   |   |   |   | P |   |   |   | 3
 +---+---+---+---+---+---+---+---+
 | P | P | P | P |   | P | P | P | 2
 +---+---+---+---+---+---+---+---+
 | R | N | B |   | K | B | N | R | 1
 +---+---+---+---+---+---+---+---+
   a   b   c   d   e   f   g   h

Fen: rnbqkbnr/ppppp1pp/8/5p1Q/8/4P3/PPPP1PPP/RNB1KBNR b KQkq - 1 2
Key: 47C539B3DEE3D29B
Checkers: h5

In order to determine whether it is checkmate, you need to check whether perft 1 is zero and checkers from d is non-empty.
For draw detection I think there is no straightforward way to do it with plain Stockfish. The only draw that can safely be detected is stalemate, similar to the checkmate detection mentioned above.


How can I read an Chess Informant Monograph I have a paperback version of A65 The Benoni by Chess Informant. This is my first monograph ever, and I cannot understand how to read it. Any ways to do it? Searching didn't help at all.

In the very first pages of the book you will find code system. It is described in 5 world languages and Serbian.

This is important to know so you can see at the end of the line what is the final evaluation of the position, if there are any novelties or alternative moves and so on.

Then you can skip the pages all the way to the line you wish to investigate.

Main line is written in bold font and the subvariations are given in normal font. This is the important part, and probably the one that confuses you:

If you see a number next to the move, something like ♘f319 this means that there are alternative moves. You can find them by searching for that number ( in our case 19 ) in the section that comes after the main lines end.

Below is the picture of what I am talking about:

You seek the number next to the move in the section marked with an arrow, at the bottom of the picture. Instead of playing ♘f3, from our example above, you play the move from that section.

That's it! If you have further questions leave me a comment ( for now there is nothing else I can do to help because your question is not specific enough ).

Hope this helps, good luck!


Is it possible to manually alter initial values in a chess engine? I am curious of the games that would arise if I changed the initial  value of a knight to -1 or make standing on e5 worth -10 points.

How would I go about to create such an engine? Is it possible to alter an  existing engine in such a way and let it play against itself?

Yes. You can download the source code for Stockfish here. Once you have done that you need to work out where the evaluation functions are and change them according to your requirements. Then recompile and run.


How to proceed in this endgame position? [FEN "3k4/ppp3pp/1b6/8/PP6/4BpP1/5P1P/6K1 b - - 1 24"]

This position is evaluated -4 but i cant find any plans for Black and lost. What should have been my strategy from this position ?

This is the full game :

[Event "Rated Rapid game"]
[Site "https://lichess.org/xxLijzuK"]
[Date "2020.04.08"]
[Round "-"]
[White "CorsaireBouritos"]
[Black "AKP2002"]
[Result "1-0"]
[UTCDate "2020.04.08"]
[UTCTime "06:59:51"]
[WhiteElo "1214"]
[BlackElo "1228"]
[WhiteRatingDiff "+6"]
[BlackRatingDiff "-6"]
[Variant "Standard"]
[TimeControl "600+0"]
[ECO "B02"]
[Opening "Alekhine Defense: Scandinavian Variation"]
[Termination "Normal"]
[Annotator "lichess.org"]
[FEN ""]

1. e4 Nf6 2. Nc3?! { (0.63 → 0.00) Inaccuracy. e5 was best. } (2. e5 Nd5 3. c4 Nb6 4. d4 d6 5. f4 g6 6. Nc3 Bg7) 2... d5 { B02 Alekhine Defense: Scandinavian Variation } 3. Nxd5 Nxd5 4. exd5 Qxd5 5. c3?! { (0.08 → -0.48) Inaccuracy. d4 was best. } (5. d4 Nc6 6. Be3 e5 7. Nf3 exd4 8. Nxd4 Nxd4 9. Qxd4 Qxd4) 5... Nc6 6. d4?! { (0.00 → -0.75) Inaccuracy. Qf3 was best. } (6. Qf3 Be6 7. d4 O-O-O 8. Be2 h5 9. Qxd5 Bxd5 10. Nf3 h4) 6... e5 7. Nf3 e4?? { (-0.94 → 0.70) Blunder. exd4 was best. } (7... exd4 8. Nxd4 Nxd4 9. Be3 Bc5 10. Bxd4 Bxd4 11. Qxd4 Qxd4 12. cxd4) 8. Ng5? { (0.70 → -0.42) Mistake. Nd2 was best. } (8. Nd2 Be7 9. Nc4 O-O 10. Bf4 Qd8 11. d5 Nb8 12. Be2 Nd7) 8... Be6?? { (-0.42 → 1.92) Blunder. h6 was best. } (8... h6 9. Nh3) 9. Nxe6 fxe6 10. g3?? { (1.71 → 0.13) Blunder. Qb3 was best. } (10. Qb3 Qxb3) 10... e5?! { (0.13 → 0.97) Inaccuracy. e3 was best. } (10... e3 11. f3) 11. Bg2 exd4 12. cxd4?? { (1.01 → -1.30) Blunder. Qg4 was best. } (12. Qg4) 12... Nxd4?? { (-1.30 → 0.36) Blunder. Bb4+ was best. } (12... Bb4+ 13. Bd2) 13. O-O O-O-O 14. Re1?? { (0.28 → -1.35) Blunder. Qg4+ was best. } (14. Qg4+ Kb8) 14... Nf3+ 15. Bxf3 Qxd1?? { (-1.29 → 5.46) Blunder. exf3 was best. } (15... exf3 16. Qa4 Bc5 17. Be3 Bxe3 18. Rxe3 Kb8 19. Qg4 Qxa2 20. Ra3 Qd5 21. Qxf3 a6 22. Qxd5) 16. Rxd1?? { (5.46 → -0.76) Blunder. Bxd1 was best. } (16. Bxd1) 16... exf3 17. Rxd8+ Kxd8 18. Bf4 Bb4?! { (-1.27 → -0.58) Inaccuracy. Bc5 was best. } (18... Bc5) 19. Rd1+ Kc8 20. a3 Ba5 21. b4 Bb6 22. a4? { (-0.94 → -2.07) Mistake. Rd3 was best. } (22. Rd3 Rf8 23. h4 h6 24. Kf1 a5 25. h5 Rf5 26. Rxf3 Rxh5 27. Bd2 Rd5 28. Ke2 Re5+) 22... Rd8 23. Rxd8+?! { (-1.57 → -2.63) Inaccuracy. Rc1 was best. } (23. Rc1) 23... Kxd8 24. Be3?! { (-2.54 → -3.85) Inaccuracy. h4 was best. } (24. h4 Kd7 25. Be5 a5 26. bxa5 Bxa5 27. Bxg7 Ke6 28. h5 c5 29. Kh2 c4 30. Kh3 Kd5) 24... Bxe3 25. fxe3 g5 26. g4?! { (-2.39 → -3.53) Inaccuracy. h3 was best. } (26. h3 h5) 26... b6?? { (-3.53 → 0.00) Blunder. Kd7 was best. } (26... Kd7 27. Kf2 c5 28. bxc5 Kc6 29. a5 Kxc5 30. Kxf3 b6 31. a6 Kc4 32. Ke4 b5 33. Kf3) 27. b5?? { (0.00 → -2.46) Blunder. Kf2 was best. } (27. Kf2 Ke7 28. Kxf3 c6 29. Ke4 Kf6 30. Kd3 Ke5 31. e4 h6 32. h3 Ke6 33. Kc3 Ke5) 27... Kd7? { (-2.46 → -1.22) Mistake. Ke7 was best. } (27... Ke7 28. Kf2 c5 29. Kxf3 Kd6 30. Ke2 Kd5 31. Kd3 Ke5 32. Kd2 Ke4 33. Ke2 c4 34. Kd2) 28. Kf2 Kd6 29. Kxf3 Kc5?? { (-3.08 → 0.00) Blunder. c6 was best. } (29... c6) 30. e4?? { (0.00 → -2.66) Blunder. Ke4 was best. } (30. Ke4 c6 31. bxc6 Kxc6 32. Ke5 a6 33. e4 b5 34. axb5+ axb5 35. Kf6 Kd7 36. Kf7 Kd6) 30... Kb4?? { (-2.66 → 12.85) Blunder. Kd4 was best. } (30... Kd4 31. h3) 31. e5 Kc5 32. Ke4 h5 33. gxh5 g4 34. e6 Kd6 35. Kf5 Ke7?! { (25.19 → Mate in 9) Checkmate is now unavoidable. Kc5 was best. } (35... Kc5 36. e7) 36. h6 Kf8 37. Kf6 Kg8 38. e7 Kh7 39. Kg5 { Black resigns. } 1-0

This is a very common kind of endgame, where you have a pawn majority on one side and fight against a single pawn in the center. Winning this is not difficult, but let's first look at your game...

You

fixed the position of the queenside pawns by playing b6 (to which white cleverly replied b5
ran with your king towards the queenside

Basically you should do the opposite:

keep your king in the center close to the white e-pawn (say around e5, d5, e4 or c4), which white cannot advance
try to create a passed pawn on the queenside: for this you want to start with a6 or c6, not b6.

The idea then is to have that a-b-c passed pawn run,  forcing the white king away from the protection of the kingside pawns

One possible line with comments....

[FEN "3k4/ppp3pp/1b6/8/PP6/4BpP1/5P1P/6K1 b - - 1 1"]

1... Bxe3 { Perhaps not the computer's first choice but a decent practical human decision to turn it into a clearly won pawn endgame. Could perhpas have delayed this exchange to gain an extra tempo (for centralizing the king) since white does not have any good moves. } (1... a5 { Prevents white from playing a5. Objectively the strongest move in the position. The main idea is to keep the white king out of play for as long as possible. } 2. bxa5 (2. b5 Kd7 3. Kf1 Kd6 4. Ke1 (4. Bd2 Kd5 { and white does not get anywhere as the king is bound to the protection of the f2 pawn, black can just collect the a and b pawns or promote the c pawn as he wishes. }) 4... Bxe3 { now is the time to exchange because black will keep the f3 pawn } 5. fxe3 Kd5 6. Kf2 Ke4 { followed by c5-c4-c3-c2-c1Q 0-1 }) 2... Bxa5 { The white king's path to freedom via f1 e1 is now blocked. Black is basically playing king+bishop+pawn vs a single bishop. } 3. h4 { trying to activate the king via h2 } 3... Kd7 { centralizing the king } 4. Kh2 Kc6 5. g4 Kd5 6. Kg3 Ke4 7. Bc5 (7. g5 g6 { the white king has no way to escape and black just pushes the c pawn to c1 }) 7... b6 8. Bf8 g6 { and black will just push the c pawn to c1. }) 2. fxe3 g5 { threatening to create a protected passed pawn on f3. } 3. g4 Kd7 4. Kf2 Ke6 5. Kxf3 Kd5 { First goal achieved: King is centralized. Note that white can never play e4 since after Kd4 white will eventually run out of moves and will have to move the king from the protection of the e pawn. } 6. b5 c6 { or a6 or c5 all will create a passed pawn for black } 7. bxc6 { basically forced because otherwise black would end up with one vs zero pawns on the queenside, which would make his task even easier } 7... bxc6 { Second goal achieved: black has a passed pawn } 8. a5 c5 9. Ke2 Kc4! { Aiminig for the a5 pawn, while keeping an eye on the e3 pawn (which would still be lost after e4 Kd4). Also the black king is threatening to get to d3 after which white would also be lost. } 10. Kd2 { basically forced, because black was also threatening Kc3 after which he'd get to d3 when white runs out of pawn moves } 10... a6 11. Kc2 Kb4 12. Kd3 Kxa5 { Again this is the more human decision. Black could also go for pawn promotion with Kb3 (followed by c4...). It is important to realize that black can catch the e pawn (rule of the square). Also it helps that the lone white king is lost against the a and c pawn (even without the black king's support). } 13. Kc4 Kb6 14. e4 a5 15. Kd5 (15. e5 a4 16. e6 Kc6 17. e7 Kd7 { and the white king is lost against the a and c pawns }) 15... a4 { I am faster than you. Needs to count. } 16. e5 a3 17. e6 a2 18. e7 a1=Q 19. e8=Q Qd4+ 20. Ke6 Qe3+ { and black trades queens and will get a new queen soon on c1. } *


Is there fiction dealing with retrograde chess analysis? I am interested in retrograde analysis problems, where the question usually is: 'What was the last move made?' or 'Where did the piece stand on the board before it fell from the table?'  etc. Currently I know of only two occurrences of retrograde chess analysis to have found its way into fictional literature. One is Arturo Pérez-Reverte's "The Flanders Panel", the other is Raymond M. Smullyan's "Chess Mysteries of Sherlock Holmes". The latter is not even a real novel, but retrograde chess problems presented in story format, so I am not sure whether I should have included it in my list.

Do you know of any other fictional work using retrograde chess problems as an important element?

There's also A Happy Solution by Raymond Allen.  It's a short story (under 6000 words), but quaint. It appeared in The Strand Magazine in 1916.
The puzzle featured in Allen's tale was posted here in Chess.com's forums:
[FEN "2BK3N/NP1P1PPb/P4P2/3p1q2/1Q1P1b2/1pB1p1p1/p1p2pp1/1kr4r w - - 0 1"]

While Chess.com's puzzle is set up for Black to force mate, it is also the board that Kenneth Dale did a retrograde analysis on.  The game was between Sir James Winslay and Lord Churt.  When a banknote was found to have been pilfered, Churt's secretary Gornay was remembered to have been watching the game, but no one could vouch for how long.  Gornay's innocence appeared inviolate, as he was also remembered to have made several remarks on some of the past moves of the game at its conclusion:

"If the play was rather eccentric sometimes, I must say it was bold and dashing enough on both sides," Gornay commented. "For instance, when Lord Churt gave up his knight for nothing, and when you gave him the choice of taking your queen with either of two pawns at your queen's knight's sixth." He turned to Churt. "Possibly you might have done better to take the queen with the bishop's pawn instead of with the rook's."

After this, the missing note was found in the wrong envelope, and Dale suspected that Gornay may have been the one who had moved the note, in order to frame Dale in case of the note's being found.

"Was he in the library all the time you were playing?" Kenneth asked.
"I can't say that," Churt replied. "I don't think he was. I didn't notice particularly. But I am positive that he did not enter or leave the room while I was standing looking at Winslade's move, and he must have been there when Winslade offered his queen and when I took it, because he was commenting on those very moves after the game was finished, and suggesting that I might have done better to take with the other pawn. You heard him yourself."

Dale later proved that Gornay could have figured out those previous moves simply by looking at the resigned game, and therefore had been free to leave the room and do his dirty work while the game was still underway.


After a blunder, is it better to resign or keep playing? I often wonder if it is better to resign or keep playing at a disadvantage after making an obvious blunder (for instance, leaving a piece hanging, only to realize too late that you made the mistake).

Let me be clear: I am referring only to casual games (not tournament), and my main goals are 1) to have fun and 2) to improve.

It can be frustrating to keep playing at a disadvantage, but does that additional challenge help make you stronger, or is it better to just resign and start a new game?

An example would be the game below, where I blundered (black) on move 13 and left my bishop hanging... should I keep playing or resign?

 [FEN ""]

1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Ng5 d5 5.exd5 Na5 6.Bb5+ Bd7 7.Bxd7+ Qxd7 8.Nc3 Nxd5 9.d3 Nc6 10.O-O Nxc3 11.bxc3 O-O-O 12.f4 f6 13.Ne4 Bc5+

First, I would try and keep a very straight face, and maybe your opponent will "trust" you, and overlook the blunder. It has happened before even with very strong players.

That said, if the opponent takes it, you should probably decide based on your level of skill and your perceived level of skill of the opponent, and if the position is messy.

For example, if you are playing a master, and the position is just a clear piece down, you should probably resign. If you are playing an 800-player, then it is very possible that you can play on despite your error.

What I mean by "messy" is if the position is a tactical mess even without the piece, it is more likely that your opponent can still make an error, but if it is just a clear piece down with no tricks, as in the position you gave, then you may as well resign if your opponent is a reasonably decent player.

Lastly, is it a blitz game, or an over-the-board tournament game? (I know in this case, you said it was casual.) If it is blitz, it really does not matter as much either way since it will be over soon; but if it is OTB, it matters more, but your opponent also has that much more time to figure things out.

In the end, there is no right or wrong answer, and you have to evaluate the circumstances, and do what you think is best at that moment.

Do keep in mind that if it were a tournament game, that playing it out may also tire you for the next game.


Official rules for castling in Chess960? (Is there a loophole?) Note: this is another rules-lawyering question.

I first ask for an official source I am calling into question the phrasing of the rules. Then I consider a few plausibly official sources, and point out a loophole (unsurprisingly not the first time castling has come under fire) - is my reading correct?

Preamble: Is there an official source for the rules on Chess960 castling?

Common knowledge at this point is that castling in Chess960 can be informally described as:

the king and rook end on the same squares as in regular chess,
the king and rook should not have moved before,
the squares the king and rook need to "slide through" must be empty,
the king should not be in, or pass through, or end in check.
(And the castling cannot be made with a promoted rook).

How about an official source?

Well, one would start by looking at the FIDE Laws of Chess as usual; the section Guidelines II is on Chess960 Rules. Disappointingly, only articles II.3.2.5.2 (specifying king and rook final squares) and II.3.2.7.4 (specifying passed-through squares must be vacant) seem relevant; no mention is made of the king being in or passing through check. So we assume that regular article 3.8.2 (specifically 3.8.2.2.1) applies to cover those.

Alternate sources would be Wikipedia (which cites for some reason dwheeler.com), and the organisers of the recent World Fischer Random Chess Championships, chess.com. Those read largely the same as the FIDE Laws.

The loophole

Consider the following position in Chess960. (wKb1, wRb1, bKe8, bRa1).

4k3/8/8/8/8/8/8/rR2K3 w Q - 0 1

Assume also that it's white's turn, and the white king and rook have never moved before. Can white castle left? Applying a little common sense, the answer is no (if we make the move, the white rook goes to d1 and the white king ends in check on c1).

However, according to every ruleset above (FIDE, Wikipedia, chess.com), all the criteria for castling have been met. In particular, in the diagram position, the black rook does not attack c1 nor d1, so the king is not moving through check. The relevant clause of the FIDE Laws is 3.8.2.2.1:

  [Castling is prevented temporarily] if the square on which the king stands, or the square which it must cross, or the square which it is to occupy, is attacked by one or more of the opponent's pieces.

Which is not the case in the diagram.

One way out of this would be to invoke article 3.9.2 of the FIDE Laws:

  No piece can be moved that will either expose the king of the same colour to check or leave that king in check.

Which by unfortunate phrasing, is ambiguous in the context of castling, which is "A move of the king and either rook of the same colour..." (Article 3.8.2), i.e. a move of two pieces. In the diagram position, moving the king alone, or the rook alone, will not expose the white king to check.

So I call attention to this loophole here. To summarise this question:

Is there an official source for castling in Chess960?
Is there an error in my reading of the rules that there is a loophole?

Hi thanks for your questions Remellion. I have a better answer for Q2 than Q1, but bottom line there is no loophole in the FIDE Laws.

(1) I don't know of and can't locate any other official source of Chess960 rules other than FIDE rules.

(2) There is a second place in the FIDE rules where we are told how naughty it is to leave a king in check:

  FIDE Law 1.4.1 Leaving one’s own king under attack, exposing one’s own king to attack and also ’capturing’ the opponent’s king is not allowed.

This would apply independently of the number of pieces involved in the castling. So there is no loophole.


How to play this bishop & pawn endgame? [Title "Black to move"]
[StartFlipped "0"]
[fen "6k1/p4p2/1p2pPp1/7p/3Pb2P/1B2P1P1/P7/2K5 b - - 0 33"]

I'm Black. In the game I deliberately allowed White pushing the pawn to f6, I was expecting something like ...g5, ...Kh7, ...Kg6 to pick up the pawn. But then I realised after ...g5, White has Bc2 which forces the exchange of the bishop. Once the bishop is exchanged, white should win with the passed d-pawn after e4 & d5.

Question: What's the best continuation for Black here? Can I take advantage of the weak f6 pawn? I don't have a computer with me, so computer analysis is fine. My human evaluation is very danger for Black (thus I'd misevaluated the endgame by allowing it to happen).

If White tries to hinder your plan by exchanging the bishops he loses the pawn endgame. I have provided brief analysis in the below diagram, see the sublines. Then I have tried to play this endgame with both colors versus computer.

Computer chose 1...Kf8 as strongest but with some "only moves" I managed to save the draw. This is illustrated in the below diagram as the main line.

I played your plan with ...g5 + ...Kh7 but computer found good resource in Be8!, which secures a draw. You will find my play as Black in the below diagram as a subline.

To conclude: you can not exploit your advantage because White generates enough counterplay thanks to your kingside pawns being on the color of your bishop.

[StartFlipped "0"]
[Title "Black to move"]
[fen "6k1/p4p2/1p2pPp1/7p/3Pb2P/1B2P1P1/P7/2K5 b - - 0 33"]

1...Kf8 (1... g5 2. hxg5 Kh7 3. Ba4! (3.Bc2? Bxc2-+ 4.Kxc2 Kg6 5.e4 Kxg5 6.e5 Kf5 7.Kd3 $8 b5 $22 8.a3 a5 9.Ke3 b4 10.axb4 axb4 11.Kd3 b3 $8 12.Kc3 Ke4!-+) 3...Kg6 4. Be8!= $8 Bf3 5. Kd2 Kxg5 6. Bxf7 Kxf6 7. Be8 Kg5 8. Bd7 Bd5 9. a3 Kg4 10. e4! Bxe4 11. Bxe6+ Kxg3 12. d5 h4 13. d6 Bc6 14. d7 Bxd7 15. Bxd7 h3 16. Bxh3 Kxh3=) 2.Ba4! a6 3. Bd7! Kg8 4. Be8! Kf8 5. Bd7 Kg8 6. Be8 Kf8 7. Bd7 Kg8 1/2-1/2


The slowest Fool's Mate in Chess960 The fastest Fool's Mate in Chess960 is obviously 1. d4 g5 2. Qxg5# with any ..Q.BRKR setup, which even beats standard chess. But which is the starting position with the slowest mate? I checked a few positions with Olive and all were helpmates in 3 (assuming White starts, which is not the default for h#). I daresay this is the maximum (Googling gave no hits).

I think there can be no slower one than mate in 3. My standard checkmating attempt would be like the starting positions 1.e4 e6 2.Ke2 Qh4 3. pass Qxe4#. What can go wrong there? 1. Ke2 could be illegal in a position like Kb1 Qh8. With the king on b1 the a1 piece has to be a rook per rules of piece set up. In this case 1.a4 g5 2.Ka2 Qd4 3.Rb1 Qxa4#.
So finally we are left with a knight being a blocker. This can only be the case if there is a knight next to the king. In that case there is a knight on the opposite side that can go for a suffocated checkmate. So if we have e.g. Ke1 Nd1 then the Nd8-e6 can go to f4xg2 or d4xc2 for checkmate. If either is only defended once, white can put the defending piece on the respective square. So the only case left is the one where both these squares are defended twice. Furthermore there can't be a heavy piece on either side of the king as otherwise the original mate would work, with a pawn advance diagonal to the king, king advance and the heavy piece blocking the retreat path. The position that's left over is something like this
[FEN "brnknqrb/pppppppp/8/8/8/8/PPPPPPPP/BRNKNQRB w - - 0 1"]

In that case the defending queen can only be on one side of the board, the other side is defended by bishop, rook or knight in some combination. In that case if it is a rook that rook can move out of the way a la b3 Bb2 Ra1. A defending knight can move away to no longer defend, with two moves left over to fianchetto either rook or bishop.
This can only go wrong if the non queen side is defended by three pieces, however this does not work as the bishop not defending that pawn has no room. (both the defending knight and rook as well as the rook on the other side plus the king have to be on the same colour leaving no room for the bishop)
Sorry for the many edits, I hope I cleared up my not so clean initial explanation.


Capture towards the center vs. undoubling There is a spoken advice to capture with the pawns always towards the center. This situation let me think for a while. Is undoubling here not better?

In this particular position both ...ab6 and ...cb6 are reasonable.

Generally speaking I would prefer to take toward the center because the doubled pawns are not weak at all when they have neighbours and the enhanced control of the center might prove useful.

Here however ab6 has the minus that it allows White counterplay thanks to the outside passed pawn after a4-a5.

The evaluation of this position will depend on Black breaking through or not on the kingside, with ...Rf3 or ...g4. My intuition is that White should be able to hold. If that's correct, the best choice might very well be to limit counterplay with 1...cb6. But once again, this is merely due to the specifics of this particular position, and not because undoubling would be better than taking toward the center in general.


Four way chess -checkmate My friends and I have been playing knightmare chess in a four player variant. We were playing with the stipulation that when a player is checkmated, after his turn he removes his king from the board and his pieces change allegiance to the last player to cause checkmate.
I had caused checkmate on a player. An opponent between my turn and the checkmated player moved his bishop to cause check on the same king I had checkmated. He staked a claim to this player's pieces. I refuted his claim on the basis his bishop did not cause checkmate, only check while my pieces actually did cause checkmate. Who would get the pieces?
By definition, check is a move where a peice is threatening on his opponents next turn. According to this, I argued that I caused checkmate and was entitled to his peices.

I will need to make an educated guess as to what rules come closest to what you have described, and I think it is that:

You are checkmated whenever your king is attacked and if it were your turn next, you would not have any moves that would result in your king not being attacked.
An opponent causes checkmate on you, if at the start of their turn you are not checkmated, but at the end of their turn you are.
If at the start of your own turn you are checkmated, then your king is removed from the game and the opponent who last caused checkmate on you will gain control of your pieces.

Under these rules, merely piling on a check while it was already checkmate would not cause checkmate.

The rest of this post is background and further analysis of checkmate, that informed my answer and may help to understand it:

According to Wikipedia, it was the Persians who abandoned king capture and introduced warning of check in order to not accidentally end the game.  So let's go back in time before the introduction of checkmate and reanalyse.

In two-player chess checkmate is a situation where at the end of your turn all parties are certain that you will (be able to) capture the king on your very next turn (and in two-player chess there exist no reasons not to actually capture the king).  Because of this certainty of how the next two turns will play out (a doomed evasive move and a certain king capture), there is no point in actually playing those moves, so both can be (and have been in FIDE chess) eliminated from the game with no detriment to the game.  (Very much the same thing happens when a player forfeits the game upon realizing that the game is lost and there is no point playing any further.)

But if there are three or more players a third party can intervene on behalf of a threatened king and (unless the game ends when the first king is captured) there may be more pressing matters than capturing an opponent's king left in check (like defending your own king).  These differences make it impossible to say with certainty when king capture is actually going to take place before it actually happens, thereby invalidating the reasoning which allowed us to eliminate king capture from the (end of the) game.

It is of course possible to try and use a definition of checkmate that is equivalent to the full checkmate described above in two-player chess also in chess with three or more players.  Indeed checkmate is usually defined in an operational way that is equivalent to full checkmate in two-player chess: your king is attacked and you have no move that will result in your king not being attacked.

When you try to use that definition in multi-player chess you will need to think about on which player's turns one can be checkmated.  If your king is attacked and you have no move that will result in your king not being attacked, because it is not even your turn, are you checkmated?  Apparently that was something you rejected, but then it becomes hard to say who checkmated you.  It is possible for example that the player before you causes your king to be attacked by moving one of their pieces out of the way of a third player's piece, and even causes you to not have any moves that result in your king not being attacked, even though they are not even checking you with any of their own pieces.  Have they checkmated you?  I think most people are inclined to say yes.  But if you want to know if they caused checkmate or not, then you need to be able to say whether or not you were already checkmated before their turn or not.  Thus you need a way to determine checkmate even when it is not your turn.

One extreme is to say that every check from a player not immediately before you is checkmate (because as it is not even your turn you have no moves to remove that attack).  Another way is to pretend that it were your turn and see if you could do something.  I have recently even read rules for multi-player chess where it actually becomes your turn if you are checked, and the player whose turn it would have been had you not been checked continues after you (and you may or may not forfeit you actual next turn).


Engine not necessarily playing strong but "attractive" Does anyone know a chess engine that is not programmed to be as strong as
 possible, but to play "attractive" chess ?

The program should have an aggressive style and play for mate attacks, even
 if the attacking moves are not quite optimal. Or at least, the program
 should trade some panws early to avoid very closed positions which tend
 to take an eternity between engines to be finished.

On the other hand, the program should not play too weak. The rating should
 at least be about 2000 Elo.

Does anyone know such an engine ?

Many engines have adjustable parameters, which allow to alter their playing style. If you mess around it a bit, you can create whole 'engine personalities'...
Here, for example, someone though it interesting to create a personality called, the Komodo Kinghunter. Apparently, it does exactly what you are looking for - plays aggressively and not necessarily optimally. Note that I have not tested it myself.

It's different for different engines (I remember most of these at least used to be configurable in stockfish) and graphical interfaces, but
some typical factors one can usually twiddle with (at worst by going to source code and recompiling) are:

Contempt Factor

  The Contempt Factor reflects the estimated superiority/inferiority of the program over its opponent. The Contempt factor is assigned as draw score to avoid (early) draws against apparently weaker opponents, or to prefer draws versus stronger opponents otherwise.

Additionally, if the engine has high contempt for its opponent, it might engage in more attacking style.

Pawn structure

  Pawn structure is a term used to describe the positions of all the pawns on the board, ignoring all other pieces. Pawn structure encompasses a broad range of ideas, from the general shape of the pawns (such as closed or open) to specific characteristics of individual pawns.

So here there's a wide range of things to change engines evaluations for - double pawns, passed pawns, general structure, exchanges etc.

Mobility
A factor for how much the engine will value the piece mobility - I suppose more mobility leads to more attacking and unpredictable positions.

Aggressiveness
Self-explanatory; allows to make the engine more or less aggressive.

Cowardice
Self-explanatory; allows to define how defensive towards its own king the program should be.

Source for quotes

EDIT: I was made aware (per Student T's comment), that the engine I initially posted below is not attractive at all and in fact a clone of Rybka. I guess it was too good to be true!

If you are reluctant to do all this fiddling yourself, here's an engine which (again, I have not tried it myself, so cannot substantiate these claims in any way):

  Thanks to its finely tuned positional vision, Vitruvius shows a readiness to sacrifice a pawn or two, the exchange and sometimes even a whole piece, for purely positional compensation.

And named among its strengths:

  Playing strength above the 3100ELOmark; Detects and exploits zugzwang positions; Very human and speculative approach to the game

Also of interest: this Vitruvius article

Unfortunately, it is not free.


What is a "tornado" in chess? I am going to ask and answer this question since I played in one for the first time in almost 40 years yesterday, and because I find it surprising that no one has asked this previously.

So, "what is a "tornado" in chess?"

I do not know if this term is used in other countries, but in the U.S., a “tornado” is a swiss chess tournament with four rounds in one day, typically at a sudden death in 60 minutes time control. It was probably given that nickname because your mind is spinning from so much chess in one day.

I played in the “Queen City Tornado” yesterday, and there were rounds at 10 a.m., 1 p.m., 3:30 p.m., and 6 p.m.. It makes for a very long day.


Options for breaking the Giuoco Pianissimo wide open? I don't like the Giuoco Pianissimo

[FEN ""]

1. e4  e5
2. Nf3 Nc6
3. Bc4 Bc5
4. d3

because I find it very slow and boring.  The cramped center and overall board make me want to just resign, so as black how can I avoid the Giuoco Pianissimo as black if white plays 4.d3 (Although I guess this is not actually possible if white does play 4.d3),so instead, what are my options for basically blowing up the center and creating a wide open game after 4.d3?

After 1. e4 e5 2. Nf3 Nc5 3. Bc4 Bc5 4. d3, you could continue with 4. ... Nf6 and aim to follow this up with an immediate 5. ... d5 if you want to open the center. For instance, play could proceed with 5. O-O d5 6. exd5 Nxd5 7. Nc3 Nxc3 8. bxc3 O-O, and you would have a rather open game.

But White need not allow this, and would likely instead play the natural 5. Nc3, bringing us into the Italian Four Knights, and stalling the idea of a ... d5 push by Black. The thing here is, White has concentrated a lot of attention on the d5 square precisely so that it is difficult for Black to play this freeing ... d5 move, which would immediately relieve Black of any hint of a cramped position. Black would now need to do some prep work in order to make this central advance happen, if that is what she wants. She might play e.g. O-O, d6, Be6 first, so that the move ... d5 is properly supported. Of course White will be playing his own moves in the meantime, and if he wants to keep things quiet for a while, he can often make it so that Black can only upset this at her own peril. But with the sort preparatory moves I've indicated, ultimately White cannot prevent you from getting ... d5 in and opening things up in a safe way.

I'm going to speak below to something more general that your question brings to mind, as it might be useful. Feel free to ignore if not, though.

One point worth making here is that some games just will be, to use your words, more "slow and boring" than others will. It's all well and good to prefer more open, dynamic, active games. But it can be a bad idea to insist upon a "faster" and more open game if doing so means recklessly putting oneself in danger, and it often can mean just that. An alternative approach (and one that will go far in leading you out of your beginner phase) is to try to see the slower, more closed phases of your games as not so boring after all, and realize that a lot can be going on "under the hood," so to speak. (Besides, the moves you play during "slower" phases are crucial to your success/failure once the position does open up.)

To illustrate this idea (very lightly), suppose our game proceeded, after 5. Nc3, by 5. ... h6 6. Be3 Bb6 7. O-O O-O 8. Nd5 d6 9. a4 Nxd5 10. Bxd5, and Black, desperate to open the game via an ... f5 push, plays 10. ... Kh8 in order to get out of the pin from the bishop on d5. White responds with 11. Qd2, and we have the following position:

So far, a pair of knights has been exchanged, but all the pawns (and everything else) are still on the board, and things have indeed been rather closed and quiet. This doesn't mean interesting things haven't been happening, and in particular, White has developed his pieces well so that it still isn't a good idea for Black to try and open the position without further preparation: 11. ... f5? is met harshly by 12. Bxh6, which wins a pawn because of 12. ... gxh6?? 13. Qxh6#. Instead, Black could play 11. ... Bxe3 12. fxe3 f5, and she has finally achieved the kind of opening of the position that she has been after.

My main point: sometimes one simply must be patient in chess, or else accept the consequences. Wanting to blast open the position only because, well, you always want to blast open the position, is going to lead you into a lot of trouble and missed opportunities. Sometimes you will find yourself in positions where it would be to your objective advantage to keep the position closed (maybe your opponent has a very cramped position that will ultimately prove fatal), but if you were to always blindly favor opening the game up, you would miss out on that kind of winning approach - or worse, you'll open yourself up to the kind of punishment illustrated above - and you will ultimately have worse results than you rightly should. Just something to keep in mind as you continue to explore the game.


What was the time control in tata steel tournament? Does anyone know, what the exact time control was for the groups A and B in the
 tata steel tournament last month ?

I remember something with 100 minutes for 40 moves and 50 minutes for 20 moves
 and 15 minutes for the rest and 30 seconds increment from move 1. Is this
 correct ? And was the time control identical for group A and group B ?

http://www.tatasteelchess.com/tournament/information

Time control

The time control is: 100 minutes for 40 moves, followed by 50 minutes for 20 moves, then 15 minutes for the remaining moves with 30 seconds cumulative increment for each move starting from the first move.

So you remembered correctly.

And, yes, should be the same for A and B.


Chess as random process Not sure whether this is more of a physics or a chess question.

Looking at the evaluation graph (computer evaluation vs. move number) of a game of chess, I realized that there are some similarities to the physics model of escape from a local potential minimum. Let me explain:

While none of the players make a mistake the evaluation will stay at values around zero corresponding to a draw. This I would associate with the motion of a particle in a local minimum, whose coordinate (=evaluation) might fluctuate a bit around the minimum value.

If a player makes a mistake, the evaluation will increase to let's say +2, corresponding to a won position. Normally (i.e. with a very high probability) white should win this game. Until mate, the evaluation will further increase to +3, +4, +5....

This process is similar to the escape from a local minimum. A blunder can "activate" the particle so that it can leave the local minimum and it will subsequently accelerate to larger coordinates (evaluation increases).

Have there been any studies on chess using such model?

Does it make sense at all?

I'd argue the process you're talking about can be represented by Markov Chain. It solves the continuous problem raised by @Brian.

I don't know where to find a proper state diagram for your question.The following diagram is for a simple board game. Imagine we model the transition probability from win to lose (or win to draw) as the blunder probability, this is similar to what you are asking.

We can represent "local minimum" described in your question as an absorbing state.

More generally, if you want to assume some latent factors for making a blunder (e.g. bad opening, personal issues), you could generalize to hidden markov model. It's possible to use the EM algorithm to fit a model from engine PV evaluations.

Given a fitted model, you can query the probability of a blunder given a chess game.

  Have there been any studies on chess using such model?

No studies that I am aware of.