What defines the name of a gambit? What defines the name of a gambit? To be obvious, if someone were to use a gambit often (of their own theory), you would name that gambit after them or so, right (like the Ruy Lopez opening)? How then do we get the names of the gambits?

There is no general rule in naming openings or opening lines in general or gambits. Sometimes it’s the inventor, sometimes the place they lived, they were born, they played the line the first time, and so on. To make it more complicated, openings can have different names in different languages. In German, the Petroff defence is named Russian defence, and Benko Gambit is called Wolga-Gambit. The Sokolski is also called Orang-Utan. So there really is no general rule but in some cases some amusing histories.


What is the best chess magazine in the world? And what makes a great chess magazine today? When I was growing up in the 60's and 70's it was the Russian magazine Shakhmatny Bulletin according to Bobby Fischer. In our chess club we generally believed that the reason the club's best player was the best player was because he had a subscription. He was a lecturer (or what Americans call a professor) in Russian at Durham University and translated into English most of the chess books in your library by Russian authors (Kasparov's My Great Predecessors, for example).

For Kasparov it was Chess Informant from the former Yugoslavia.

What characterized these two publications was that they were mainly just game scores of the strongest players around the world, mostly east European. Although Shakhmatny Bulletin was in Russian since the games were unannotated you really only needed to know the Russian annotation for the pieces. Informant was completely language free.

Nowadays there is little call for such games collections because we all have chess databases with online updates from The Week In Chess and ChessBase. What we want in a chess magazine is top class analysis of the best games and the latest inside news. The nearest I can come up with today is the Dutch magazine published in English, New in Chess, but all I have to compare it with are more parochial English magazines like BCM and Chess. I've never even seen a copy of the American magazine Chess Life, for instance.

When I lived in Germany I used to occasionally read a German magazine called Kaissiber which I thought was very good but rather difficult since it was in German.

Is NiC currently the best chess magazine out there? Or should I be reading something else?

Chess Informant and Chess Life are targeting very different strata; it is not possible to compare them.

When I was growing up in 60s and 70s - in Soviet Union - we the amateurs were reading "Shakhmaty v SSSR" and "64". I didn't bother reading the Bulletin until I reached a Kandidate Master level. The Informant was of use for professional only.

Books were much more important than magazines. Every serious tournament (such as USSR championship, Chigorin, the Interzonal, etc) was followed up with the corpus of heavily analyzed games. There was also an unspoken rule (attributed to and driven by Botvinnik) that each Grandmaster must publish at least one book.

Sorry for ranting.


Is it always better to accept gambits? Among chess players circulate the idea that any gambit should be accepted. It's an old and popular idea; if you don't want trouble, accept the gambit. Should this be consider a valid principle?

This is really dependent on

which gambit
the style of play you prefer.

For 1, consider the King's Gambit. The theoretically preferred line for Black is 1. e4 e5 2. f4 exf4 3. Nf3 d5! which immediately returns the pawn. On the other hand, in the main lines of the Benkö gambit, White holds a pawn advantage well into the late middlegame.

As for 2, I'm usually fine with having a material advantage, defending against an attack, simplifying and winning in the endgame. Other people like having the initiative and will usually try to return the gambited pawn in exchange for a (counter)attack.


Good openings for a beginner (for white) I am a beginner in chess and I like to play some of my friends who are basically at the same level. Usually who wins is based on who makes that one amazing (and lucky) move and quite frankly I want to gain an edge over my friends. I have noticed that I usually just open randomly and this is what happens most of the time:

One of the sides (or both) are neglected and both of my rooks are trapped for the entire duration of the game until most of my pawns are decimated and my rooks have some moving space. I have noticed that a lot of beginners/casual players have the same problem, since it seems to take a lot of moves to properly free up space for a rook.
Only the pieces which I gave space at the beginning (which usually are my queen, 1 bishop and both knights since they are never trapped by pawns and of course a couple of pawns) are used and the other pieces are totally neglected, kind of the same as the first point only more general.

Some my final question is:

Is there a simple opening for beginners which frees up a lot of space for the powerful pieces to be utilized, especially rooks?

p.s. -  I am aware that there exists no perfect opening, but keep in mind this is very low level chess. So I'm looking for an opening which is usually enough to have a nice setup and is not countered easily by weak players.

The Scotch Game is definitively an opening for beginners (playing as White).

It's opened game that permits to player having two bishops free easily (see behind). Moreover, theory is simple and this opening is not countered easily by weak players because few weak players know it.

Here's a diagram:

[fen ""]

1. e4 e5 2. Nf3 Nc6 3. d4


"Knight rebus"-Decipher an encoded chess position Here is a knight rebus. Each letter represents a different type of piece.
Uppercase letters are one color and lowercase letters are the other.
Determine the position. If possible, also determine the previous moves.

n and N are kings and h is pawn. What is the rest?

Assume the board is in it's usual position (the bottom row is the first row) then this is the solution:

[FEN "1B6/8/1k6/R7/1n6/2K5/r6p/q1r1n3 - - - 0 1"]

and Black's last move was b2xc1R++.

I could write an explanation here about I came to this result, but it would essentially be copying @Maxwell's answer. I didn't use it, though.


How does black ensure a draw in this R+3P vs. r+2p endgame with all pawns on the same side? From a recent world-championship game Fabiano Caruana vs Magnus Carlsen (2018), the players agreed to a draw here:

[Title "Black to move"]
[FEN "8/1r3kp1/7p/7P/4R1P1/6K1/5P2/8 b - - 2 54"]

However, I played this position as black against the computer, and it quickly crushed me.  Obviously I'm doing it wrong.

Question: How does black ensure a draw in this rook and pawn endgame?

My play was rather planless (basically I don't know where to put the king and rook---I think the pawns should not be moved), so after a few "I don't really know what to do, but this move isn't immediately losing" moves, I end up having to make critical moves, then end up making a mistake.

I played several times vs. the computer now; here's one example:

8/1r3kp1/7p/7P/4R1P1/6K1/5P2/8 b - - 2 54

54... Ra7 55. Kf4 Kf6 56. Rc4 Ra5 57. Rc6+ Kf7 58. f3 Rg5 59. Rc7+ Kf6 60. Rc6+ Kf7 61. Ke4 Ra5 62. Rd6 Ke7 63. Rc6 Kf7 64. Rd6 Ke7 65. Rd5 Ra4+ 66. Kf5 Kf7 67. Rd7+ Kg8 68. Ke6 Rf4 69. Rd3 Rf6+ 70. Ke5Kf8 71. Ra3 Kf7 72. Ra7+ Kf8 73. Ke4 Rb6 74. Kf4 Rc6 75. Ke5 Rf6 76. Ra3 Kf7 77. Ke4 Kf8 78. Ra8+ Kf7 79. Ra7+ Kf8 80. f4 Rb6 81. Kf5 Rc6 82. Ra8+ Kf7 83. Ra7+ Kf8 84. Ke4 Rc5 85. Rb7 Kg8 86. Rd7 Kf8 87. Rd5 Rc4+ 88. Kf5 Rc6 89. Ke5 Kf7 90. Rd7+ Kf8 91. Rd6 Rc5+ 92. Ke6 Rc8 93. Kf5 Re8 94. Kg6 Re7 95. Rd8+ Re8 96. Rxe8+ Kxe8 97. Kxg7

(I'm not sure what I'm doing wrong with the replayer here.)

Sometimes the computer would draw because it didn't seem to playing for a win (e.g. pushing pawns, or just letting them hang).

The following explanation is for the general 3 vs 2 pawns on one side situation, which does apply also to this game. Of course the situation is the same whether the pawns are on the a-c files or on f-h files.

This is a fairly simple draw if you follow a few simple rules:

don't exchange rooks
do exchange pawns whenever possible
keep your king close to your pawns
if necessary block the enemy king or check using your rook

If you do this, your opponent should not be able to enter your camp or bother you with checkmate or anything.

That leaves your opponent with one winning attempt only, which is to create a passed pawn in the center (here on the f-file).

In order to prevent this, the usual recommended set-up is to push the pawn on the border of the board forward (here the h-pawn) and to protect it with the pawn on the adjacent file (here g-pawn). (This setup is already realized in the quoted game with black pawns on g7 and h6.)

This setup ensures that in order to create a passed pawn, the opponent has to exchange all other pawns first.

The resulting position with rook+pawn vs rook should then be an easy draw as the defending king is placed close to the queening square of the pawn.

The same general rules apply to 4 vs 3 pawns + rooks endgames. A good pawn structure for the defending side would be h5-g6-f7 (or similarly on the other 3 corners of the board). 4 vs 3 pawns is slightly more tricky as there are more pawns that need to be exchanged in order to secure a draw.


Castling in XBoard's edit mode Probably a stupid question, but I use XBoard with Fairy-Max or GNU Chess. In the edit game mode, or in analysis mode, it is not possible to castle under any circumstances. Is there some setting I am missing?
Edit: Here is an example:
For the position:
1.e4 e5 2.Nf3 d6 3.d4 Nf6 4.Nc3 Nc6 5.Bc4 Be7
I would like to play 6.O-O. Typing the move in returns "{White mates} 1-0". Dragging the king over two spaces returns "illegal move". Doesn't matter which engine is selected. I can castle while playing against the computer, however.

According to XBoard's manual [ref. 1]:

  "...XBoard 4.2.7 and earlier... The internal move legality tester
  [had problems with] castling or en passant-capture rights."

If you're running 4.2.7 (or earlier), then a newer release should solve this problem.

Caution:  Although this is not relevant to the specifics of the question, I feel that if you are running this version, then it would be remiss of me were I not to mention that there is also a reported security risk (mid-grade: stack overflow) inherent to XBoard 4.2.7 [ref. 2, 3].

References:

https://www.gnu.org/software/xboard/manual/xboard.html#Limitations
https://www.cvedetails.com/vulnerability-list/vendor_id-2551/product_id-4447/version_id-19153/Tim-Mann-Xboard-4.2.7.html
http://seclists.org/fulldisclosure/2004/Mar/40


Can I download early versions of Leela chess zero? I want to play weaker versions of Leela. It would be good to play some really early versions of the net. Is there a repository available where I can download them?

For early versions, the lczero project's download page refers you to the lc0 releases available on GitHub. For versions from 2018, you can go the lczero repository on GitHub.
Note that while the downloads from from the former repository (lc0) provide both Windows builds and source code, the older releases from 2018 (lczero) give you only source code that you need to compile by yourself.


What color squares should pawns be on with one bishop left? This slightly confuses me.  If I have one bishop left - let's say it is the light-squared bishop - ss it better for my pawns to be on the light squares or dark squares?  Let's assume also that my opponent has a dark-squared bishop.  The way I look at it it is like this (which is probably wrong).  If my pawns are on the light squares, I can protect them with my bishop, but they block my bishop.  If my pawns are on the dark squares, they don't block my bishop, but I can't protect them.

Does it make a difference if the opponent has a bishop left that is the same color as yours, or has no bishop left?

The rule of thumb is that the stronger side (the side trying to win) should put the pawns on the opposite color of his or her bishop (so that they don't get in the way), and the weaker side should put pawns on the same color as their bishop in order to defend them an extra time (defended with the bishop and the king, the opponent can never win a pawn).

There are obviously exceptions to this, though.  Each position really has to be judged independently.

One key idea, however, is that it is usually a good idea to block your opponent's pawns on the same color as the bishops (assuming that the two bishops are both light squared bishops or both dark squared bishops).  This gives you the chance to try and win the pawn later and it will restrict the movement of your opponent's bishop.

If you have the only bishop on the board (your opponent has a knight, for example) it is almost always correct to put the pawns on the opposite colored squares of the bishop.  This is usually the only way to play for a win.  This touches on the good bishop/bad bishop question, but if your bishop is bad, then the knight will many times have the edge.  If your bishop is good, however, you can try to make use of the bishop's superior range.


What are the best repertoire books for White with the English Opening? What are the best repertoire books, from White's point of view, with the English Opening?

In the Grandmaster Repertoire series, there are three books covering the English opening from white's perspective, written by GM Marin in 2009 and 2010: Volume 1, Volume 2 and Volume 3.

More recently, in 2016, IM Cummings wrote a repertoire book based on e3 systems, rather than fianchettoing the bishop with g3.

Update: In 2018, a new repertoire series from white's point of view is published: The Modern English, written by GM Georgiev and IM Semkov. In Volume 1, the authors discuss 1.c4 e5.


Problem with a shorter solution I'm looking at this problem.

[Title "White to move. Mate in three"]
[StartFlipped "0"]
[fen "5rb1/1p1P1pbr/1p5p/5N/PP2k/1Np3QB/6K/8 b - - 0 1"]

It requires white to mate in three. The accepted solution starts with 1. Kf1. But there seems to be a mate in 2 via 1. Ne7 and then 2. Bf5.

Am I missing something? If the mate in 2 is correct, is it common/normal for a problem to request a mate in 3 when a mate in 2 is available?

After 1.Ne7 Black has 1...f5, stopping the immediate 2.Bf5#.


Attempting to create a retraction problem I am trying to create a retraction problem, but I am unsure if it is sound, and I do not know where to find resources on them. I have two questions.

Is my problem correct? I am not giving a solution as to leave it to you to decipher.

Where can I find resources on how to make retraction problems?

I wish for feedback so I may better my creations of retraction problems.
White retracts a move and instead delivers stalemate.
[FEN "8/3R2Kp/4kP1P/3R3P/3B2BP/6NP/P1P4P/8 w - - 0 1"]

Could white have just played Bg4 from somewhere without capture? Black’s prior move was Ke5-e6. This can be fixed by a shifting wNg3 to e3 and wBd4 to g3 in its place. This stops other cooks where White has just given a discovered check. Adding a further wN on c6 also prevents any retractions with the White rook, and the Black king moving to e5.
[FEN "8/3R2Kp/4kP1P/3R3P/6BP/4N1BP/P1P4P/8 w - - 0 1"]

A key point is that retracting 1. e5xf6e.p. f7-f5 2. B~g4+ Kf5-e6 3. N~e3+ works, as wPe5 blocks wRd5 from attacking f5, and so bK on f5 only endures a single check (from wNe3).
General chess problem solving engines e.g. Popeye don’t currently offer retraction capabilities. It might be possible to solve Edith Baird style retractors though, but not ones with retro logic.
The database pdb.dieschwalbe.de contains lots of retractor problems. Type k='help retractor' in the search box, and hit Overview to begin your journey in this amazing resource.
Addendum #1 11/30/2020: Here is a sound version by Rewan, a correction of my above "correction"! It is certified correct by Mario Richter's Rawbats program. The above version is incorrect due to 1. Rf5-d5 being a possible last move for White as well, and, furthermore, multiple stalemating moves afterward.
[FEN "8/3R2Kp/2N1kP1P/3R3P/3B2BP/6NP/P1P4P/8 w - - 0 1"]

Addendum #2 11/30/2020: I found a bug with my earlier proposed version, and also a way to make this much more economical. The new solution is proved correct (aka "C+") by Mario Richter's legendary Rawbats program.
[FEN "8/3R2K1/4kP1P/3R3P/3P2BP/4N1BP/7P/8 w - - 0 1"]

White has made 15 pawn captures, so if the last move (which must have delivered check) was by an officer, then it was not a capture, so Black has no prior move, and the position is illegal. The only possible last move is en passant, R: 1. e5xf6ep# so we conclude that this definitely was the case.
(For retractors, one does not need to prove that the prior move was definitely a double hop in order to allow the en passant retraction. In this case, the logic goes the other way round: the en passant proves the double hop.)
Now the retraction goes R: 1. ... f7-f5 2. B~-g4+ Kf5-e6/Ke7-f6 3. S~e3+/R~-d7+ etc.
Instead of the first retraction, White can play 1. Se3-f5= for stalemate.
(It could be possible to generate this effect in a position in which White is not delivering check, or in which one can retract uniquely further.)


Is this a sound elephant offer? In the following dobutsu shogi position, is Gc3xc2 a bad move?

  ABC
 +---+
1|   | g
2|lce|
3|E G|
4| L | *C
 +---+

It's not a sacrifice, it's a trade after 1. Gxc2 G*b3 and taking the elephant on a3 next.

On the other hand, since doubutsu shogi is strongly solved, you can use an engine/tablebase (e.g. https://github.com/fuzxxl/dobutsu) to set up and see the solution anyway. (I haven't done this, though.)


About how to respond to this atypical black defense in the Ruy Lopez I've recently begun studying openings, and I've been practicing the Ruy Lopez.

I played a game that began as follows.

[FEN ""]

1. e4 e5 2. Nf3 Nc6 3. Bb5 d5 4. O-O dxe4 5. Nxe5 Qd5 6. Bxc6+ bxc6 7. Ng4

Generally the black response is 3... a6, and then I can either play the exchange variation or back up my bishop to Ba4. Instead, as seen, they played 3... d5. I responded by ignoring the threat to my pawn by castling. After 5... Qd5, I decided to make the exchange and backed up my knight.

Did I respond correctly? Is there a named variation for that black response? If anything it was enough to throw me off. A few moves later I traded queens and forked his king and rook, but I can't tell if my advantage came from a bad move by my opponent or as a result of his atypical opening leaving him in a disadvantaged situation.

3... d5 is not listed here so it is a safe bet there's a problem.

It looks like an overreach, with both Black pawns being vulnerable.

I'd go for a pawn steal.

[FEN ""]

1. e4 e5 2. Nf3 Nc6 3. Bb5 d5
4.Nxe5 a6 5.Bxc6+ bxc6 6.Qe2 {White has better development, better pawns, and a free pawn.}


Draw rates in classical chess between elite players? I'm looking for detailed statistics exhibiting draw rate for elite players. I did find this and this publications, however, they only contain aggregated data for 2600+ players, and arrive at a figure of about 55% for equal 2600+ players.

This strikes me as completely inadequate estimate as far as elite players are concerend. I checked randomly some pairs of top players on chessgames.com, and the draw rate is usually more like 70% to 80% (well, for Carlsen-Ding Liren it's currently 100% with the sample of 9 games). This is consistent with the data that I got by checking some random elite tournaments - they have anywhere between 20% and 40% decisive games, most of them usually between players with larger rating difference. This is also consistent with betting odds - they indicate the probabilities of draw between 75% and 83% for the ongoing Altibox Norway chess tournament.

Is there a detailed statistics on how a draw rate varies with (a) rating
 difference and (b) average rating of the two players involved, similar to one linked above but with a detailed breakdown in the range of 2600-2800? Ideally with color breakdown, so that one can extract data such as "if a 2720 player plays white against an 2770 player, then the probability of draw is such and such"...

For over 2700 rated players,  statistically the draw rate is slightly under 50%.

For all over 2200 ,  the rate is just under 40%, statistically.


How do I determine whether a game is a draw or not in case of timeout? So I played many games online where I am winning but then lose on time. Sometimes the game is drawn (when there is no sequence of legal moves that would produce checkmate) and sometimes I lose (when there is such a sequence). The decision the website takes happens instantly. I am wondering, how do they determine whether the game is a draw or not? If they use brute force, then the decision would take longer to arrive at.

As far as I know, every chess website simply looks at the opponents material to determine if they have mating material or not. It doesn't matter even if mate is possible.

The ruleset you are referring to are the FIDE rules, and for simplicity chess websites do not use these rules because the percentage of positions where self-mate is possible is too low.


How to update Elo rating? I'm building a chess app which will have a Elo rating system.

Would it be more appropriate to update player's rating based on their rating at the beginning of the game, or their rating at the end of the game?

For example, Player A (1600) plays against Player B (1700), and it took a week to complete the game (correspondence chess). During this week Player A won some other games and their rating become 1650. Player B lost some games, and their rating become 1680. Now, the game between Player A and Player B ends.

Should I update the ratings as if:

1600 played against 1700, or
1650 payed against 1680, or
something else

What would be more appropriate, and why?

Remember what a rating is: it's an estimate of the relative strengths of the players. The more information you include in your rating calculation, the more accurate it will be and the faster it will converge. At the end of an OTB game, the only new information you have is the result of that game. However, on a correspondence site, you also have the information from both players' results while the game was in progress. Why would you not want to use that information?

To update the players' ratings based on their ratings at the start of the game is to say that you think their ratings at the start of the game are a better estimate of their relative strength than their ratings at the end of the game. In other words, it's saying that you believe the ratings are becoming less accurate with time. If that's what you believe, you shouldn't update them at all!


A piece was knocked down during a blitz game I was playing a blitz game which was not part of a tournament or something but there was some bets, which were not significant at all, just to add some more spice to the game. However at some point I promote a second queen and since we didn't have spare pieces I took a rook which was already out of the game, turned it upside down so it differs from a real rook and me and my opponent agreed to use it as a queen.

However when the time pressure came and due to the fact that when the rook is turned upside down it's not so stable in my attempt to play fast moves I accidentally knocked the rook down. When this happened I lift the rook and put it correctly on the board but this time instead of turning it upside down I put it as an ordinary rook. I think it worth to mention that I didn't press the clock until I thought everything was fixed. However my opponent claimed that because of the fact that I knocked down a piece and also that I put it incorrectly afterwards the game should not count (he was losing at this point) and refused to accept defeat.

From my perspective the things that I would like to know are - is there such a rule that said :

If you knock down a piece the opponent has the right to invalidate the game
If you put a piece incorrectly (as mentioned above the rook was used upside down, but after I knocked it down I pick it up and put it as an ordinary rook) the opponent has the right to invalidate the game
Based on the facts that I described is there something that can justify invalidating the game?

When you placed an upside down rook on the board instead of a queen you made an illegal move. In blitz the first illegal move losses the game. You lost. What happened afterwards is irrelevant.

There are differences between blitz and standard chess (longer time control). In standard chess you are allowed one illegal move but the punishment is your opponent gets an extra 2 minutes on the clock. The second illegal move loses.

Actually the position in blitz is more complicated than I said above. If an arbiter sees your illegal move he will stop the game and forfeit you. If the arbiter doesn't see then it depends what your opponent does. If he claims the game then you lost. If he plays on then he accepts the illegal move and the game continues.

The problem is that your upside down rook is not a queen, it is an upside down rook. Every time you move it like a bishop (which the queen is allowed to do) you make an illegal move. If an arbiter sees you move an upside down rook like a bishop he will forfeit you the game. Your opponent can also claim the game for an illegal move every time you do this.

Your opponent cannot claim the game because you knocked pieces over. If you correct the position on your own time that is OK. If you already pressed the clock your opponent would be entitled to start your clock while you pick up and replace the pieces. If you continually do this the arbiter can give you a time penalty by giving your opponent an extra minute on the clock and then if you do it again after that he may forfeit you.


Who is best at Fischer Random chess, humans or engines? I know that the old good question about engines vs humans has been asked multiple times, e. g. here.

But what about random chess (aka Fischer chess or chess960)? Can humanity feel confortable about struggling machines in this game?

Do you know of plays or championships that throws any light about the question?

You have to understand, that a top ten player is superior to an engine in the opening, because he used engines to analyze openings for many years, and because engines usually don't have an opening book on the level of the preparation of a top player.

In chess 960 you basically take away the opening book for both players and at the very top this actually benefits the engine.

So I think there can be no doubt, that engines would be similarly superior in chess960 as in normal chess. But the only Human-Engine match I know of was still won by the human player: Peter Svidler vs Baron, 1,5:0,5 in the year of 2005.
Of course the big jump in engine strength only came with Rybka in the very same year 2005.


Black to move and mate in 3 I found this interesting problem on Reddit. If this position appears in Britz's game of mine, I also would miss this.
[FEN "5r1r/ppk3p1/8/2bB4/3n4/7b/PP4PP/RN1QR1K1 b - - 0 1"]

1. ..Ne2+
 2. Kh1 Ng3+
 3. hxNg3 Bg4# with the rook h8

Very nice puzzle !


Can a tournament allowed to run if all players are allowed to cheat? I am interested to know whether money based online chess tournament would succeed if all players are allowed to cheat.

This concept is called advanced chess or freestyle chess.

There used to be an advances chess tournament in Leon already in the late nineties. Nowadays it has reverted to a normal rapid tournament.

And there have been freestyle tournaments online (for money), first organised by chessbase and nowadays apparently continued by Infinity Chess.


What is the longest forced win with 3 to 6 pieces (ignoring 50 & 75 move rules)? I am wondering, what endgame, with 3 to 6 pieces, has the longest checkmate with optimal play? Right now, the longest I'm aware of is the two knights versus one pawn endgame, which in certain positions can take up to 115 moves for the knights to serve checkmate.
The 50 move-rule & 75 move-rule are to be ignored.

Longest known checkmate is in 549 moves, revealed by Lomonosov Tablebases.

You can see the game here.

Plus, you don't need to say "endgame" explicitly. Longest checkmates come from endgame tablebases already. And it's not possible to build a middlegame tablebase practically, because of the exponential space complexity. Let's say there is a middlegame position which is in 12-men tablebase:

---------------------------------------------
5-Men  |  ~7GB
---------------------------------------------
6-Men  |  ~1200GB
---------------------------------------------
7-Men  |  ~140000GB
---------------------------------------------
8-Men  |  ~10000000GB Estimated
---------------------------------------------
12-Men |   Do the math :-)
---------------------------------------------


Checklist before you make a move What is the checklist that you generally follow before you make a move?

I would generally look first for forcing moves (checks/captures), then moves that give me some positional edge.

It would be good to know what good players think during moves.

1) Did my opponent’s last move contain a threat? Is the threat real and something I need to respond to? Or am I able to ignore that move and continue with my plan?

2) Do my pieces have sufficient protection? Do I have a piece that is hanging? Does my opponent have an under-protected piece?

3) Is my king safe? What about the opponent’s king? Can I take advantage of my opponent’s king by, for example, preventing him from castling?

4) Did my opponent’s last move prevent the threat posed by my previous move?

5) Do I still need to develop my pieces?

6) Can I bring my rooks to an open file or in general, make them useful? Can I double up rooks on an open file? Do I need to still open files for my rooks?

7) Does my opponent have any weaknesses? What are the targets I should considering attacking (undefended pieces, under-protected pieces or squares, open king, etc.)?

8) How can I attack the target(s)? Any other weaknesses that can be exploited? What’s the plan?

9) After looking away for a few seconds and revisiting the position with a completely clean, unbiased mindset, does the move I am about to make appear to be a mistake? Am I hanging a piece? Am I falling for a forced checkmate? Did I analyze all forcing moves (checks, captures, and threats)? Are my thoughts consistent with what I am calculating?

Taken from ChessUniversity.com, but is taught to students everywhere.


In Nakamura v. Friedel in 2009, (22. Bc1) why did Friedel resign? After White's 22. Bc1, it seems like responding with Rd2 would keep the game alive for Black. I assume Friedel's a more insightful player than I am. What am I missing? That is, from an experienced player's viewpoint, why do we assume that staying alive with Rd2 is not worth the effort, and how would White be sure to win regardless?

[fen ""]
[White "Nakamura"]
[Black "Friedel"]
[Event "US Championship 2009"]

1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. Ng5 d5 5. exd5 Na5 6. Bb5 c6 7. dxc6 bxc6 8. Bd3 Be7 9. Nc3 O-O 10. O-O Rb8 11. h3 c5 12. b3 Rb4 13. Re1 Bb7 14. Ba3 Rf4 15. g3 Rd4 16. Nf3 Rd3 17. cxd3 Qd3 18. Ne5 Qf5 19. g4 Qf4 20. d4 Rd8 21. Qe2 Rd4 22. Bc1

22...Rd2 saves the queen, but black is still down a massive amount of material. After white takes the rook on d2, he has two rooks for just a bishop. With such a huge material deficit, there is no possible hope of defending with normal play. The only chance for black would be to have an immediate attack on the king or other very strong compensation, which is not the case in the game. White's king is slightly open, but black has no way to take advantage of it and white can easily cover any threats to his king. Since black has no meaningful way to generate any play to make up for the material, he resigned.


Is there a chess engine with divide perft for captures only? I'm programming a chess engine from scratch in C++, and I have it playing games on UCI against others already. I spent about four days trying to weed out bugs in my move generator, and finally did manage to make a bug-free movegen.

A few days ago, I implemented quiescence search, for which I lazily copy-pasted my movegen code to get a captures-only movegen function by simply removing all quiet move generations. I presumed it was working which was a bad idea.

I just did a perft on the captures-only function and it already failed at depth 5 on 'Kiwipete'.

For the movegen, I used Sharper for divide perft to weed out bugs. Unfortunately, Sharper does not have a divide perft command for generating only captures and I don't think the source code is available either.

Is there a reliable engine that can do divide perft on just captures?

Update 1: In light of jknappen's comment, I'd like to add more information. 'Perft' refers to performance test, which in chess programming usually refers to an operation which counts the number of leaf nodes (at the end of the tree) of possible legal moves at a certain depth from a starting position. For example, the starting position in chess has 20 leaf nodes at depth 1, while it has 400 leaf nodes at depth 2.It's used for testing whether move generators are working correctly. Refer to this.

Update 2: I used my own engine to test my capture generator (because I know that my regular movegen definitely has no bugs), and I don't see a problem. Although, I used Vice to test my capture movegen (my engine is heavily based off of this one, and I know that it has way of measuring perft), which results is number that's are off exponentially after depth 3. But when I look at the captures themselves, they work correctly. I had to change Vice's code to do the capture perft, which introduces ambiguity, and so it would be nice to have an engine that already has capture perft.

If there isn't any, I'd have to create something new that uses my already existing movegen to verify the integrity of the capture movegen. I have a hunch something is wrong, because in some games as it is about to win, it gives away a major piece (such as a queen), and ends up losing, which makes me think that it's generating captures incorrectly during quiescence (search only captures to make sure nothing is being attacked) search.

Update 3: I ended up using my own movegen to test it. Turns out, I was wrong. Tested 'Kiwipete' to depth 11 and found nothing wrong.

I'm not aware of any engine that gives you only capture moves. But you can easily do it yourself, for example, you can easily modify the move generation code in Stockfish such that it only generates capture moves.

It's probably not a good idea to test your implementation with Kiwipete. You should try positions with en-passpant capture, capture with promotion, capture with under-promotion. Once you're comfortable, then move on to the Kiwipete position.


Why do grandmasters wear suits at tournaments? Whenever I see photos of professional chess games, the players are always dressed impeccably and it's uncommon to see someone even missing a jacket.

Maybe this is a dumb question, but I don't understand why they dress so professionally, when they would be more comfortable (and perhaps perform better) in something else?

Is it to seem threatening to their opponents?  Is it to make themselves feel more confident?  Do tournament rules require it (but if so, why)?  Is there any history or tradition behind it?

In case you've never noticed, I've included some images below.

Aronian and Caruana at the previous Candidates tournament

Anand and Carlsen at the 2013 World Chess Championship

The pictures you posted are of the top GMs in the world (Anand, Carlsen, Aronian, Caruana). These GMs almost exclusively play in elite invitational tournaments, normally with around 8-10ish players. As a result, these tournaments likely have a strict dress code because the organizers want to maintain the high prestige of the event.

For example, the Bilbao tournament is a double round robin with 4-6 of the top players in the world. It's regarded as a very strong tournament, solely based off these 4-6 players. So, imagine if the players showed up wearing casual clothes, like shorts and t-shirts. The players may be regarded by fans as "less professional", which will severely damage the reputation of the tournament.

Another reason top GMs dress in suits is that they are being endorsed, or want to be endorsed (look at Carlsen's shirt in the photo you posted -- he's advertising for Arctic Securities). If a company was looking for a chess player to advertise their brand, they'll prefer the player that looks better/more professional.

Conversely, most average GMs in open tournaments do not dress in suits. This is due to the 2 reasons mentioned above, except flipped. The prestige of open tournaments do not depend on how a select few players dress, since open tournaments have hundreds of players. Also, average GMs are not going to be endorsed by big companies, so they have no incentive to dress up (unless they want to).


How to watch PGN at different speeds? I am looking for a program for Windows or an online service for viewing PGN at variable speed.  I know that lichess has fast and slow speed, but I want more adjustable settings.

My own web application can help you
https://www.apronus.com/chess/puzzle/editor.php
(1) Paste the PGN text into the 'PGN import' tab.
(2) Adjust the speed of animation on the 'diagram' tab.
(3) Click 'download animated diagram'.


Why this is the best move? I'm new here, so I just like chess and I don’t study too deeply. I could not understand the move Qxe5. Can someone explain to me?

The move exploits three things:
1. The black knight on f4 is trapped and will fall.
2. The black pawn on d6 is pinned.
3. The black King is trapped behind its own pawns allowing the threat of a back-rank mate.

Qxe5 dxe5 2. Rxd8+ Qf8 3. Rxf8+ Kxf8 and White has stolen a pawn
Qxe5 Qxb3 2. Rxd6 and White has a lovely game


En Passant vs In Passing In Lasker's Manual of Chess (written 1932 or earlier) I have just read the phrase 'in passing' referring to the en passant capture. I wonder if this expression is old-fashioned or still in use. Basically, I am interested in whether I can say 'in passing' in spoken language and still be considered correct.

The image  shows the exact context. The phrase is right below the diagram.

According to wikipedia:

  En passant (from French: in passing) is a move in chess.

As far as i can find, 'In passing' is the translation of the name of the move, however it is not actually spoken as 'en passant' is used instead.

One explanation for the appearance of this term is that Lasker, the author of the book, accidentally translated the word. According to this page, the original form of this manual was written in German, and Lasker re-wrote it in English at a later date. He may have translated 'En Passant' into English by mistake, not realising that we also use the french for the term.

  In 1926 Lasker wrote Lehrbuch des Schachspiels, which he re-wrote in English in 1927 as Lasker's Manual of Chess.


How can I minimise my opponent's chances to make use of a weak square in my position? For example, the Nimzo Indian where I don't want black to use the c4 square or the Benoni where I don't want white to use the d6 square. Is the only way to prevent this to have pieces tied down to defending that square because to me that seems like a waste.

Is the only way to prevent this to have pieces tied down to defending
that square because to me that seems like a waste.

No, it isn't the only way. There are two other better ways:

If you don't like the positions that can arise in a particular opening then don't play it. Play an opening you do like.
Normally in an opening where one side has weaknesses there is some compensation for the other player in the form of either counter weaknesses or attacking chances. Good players who choose such openings do so because they want to take advantage of those counter weaknesses and attacking chances. If they do this skilfully then their attack hits home before their opponent can take advantage of those weaknesses. But in any case they get the kind of double edged game they like.


Chess endgame database+50-move rule=potential error? Are there any examples of positions where usage of the endgame tablebase gives an incorrect evaluation, due to the ignoring of the 50-move rule? At the moment I am not sure if endgame tablebases return the information specifically regarding the 50-move rule.

You are right that tablebases do not automatically contain information pertaining the fifty move rule.

To use tablebases accurately currently engines use the DTZ50 metric (distance to zeroing with fifty move rule) which tells you the number of winning moves until the 50-move count is reset. If this number is too big, the position is evaluated as a draw. Apparently this metric can give results that are one ply off.

To get perfectly accurate results these guys recompute tablebases with the fifty-move rule in mind. The resulting metric would be called DTM50 (distance to mate with fifty move rule). One of the differences between DTM50 and normal tablebases is that the winning line depends on the ply count and not only on the position on the board. Generally the higher the ply count, the longer the winning line, because a zeroing move has to be found within the next few moves, which restricts the possibilities. Here, you'll find an article about DTM50.


Very fast chess games-tournaments between engines I am wondering if there are chess games or tournaments between engines, with a very small duration, like 10-5 seconds or 10-10 seconds (every game). If not, would it not be interesting?

At those timescales, communication between computers becomes a problem. For instance, it takes more than a millisecond (10-3 s) for me to ping my router. Even if you install a sort of timekeeper program on the computer itself, CPU clocks aren't reliable on such small timescales.

Instead, it might be more interesting to run them on slower hardware.


Why wasn’t Rashid Nezhmetdinov a grandmaster? He won the Russian championship 5 times, so why wasn’t he a grandmaster?

Rashid Nezhmetdinov, aka “Super Nezh”, was clearly GM strength, having a plus score in the 20 games he played against World Champions, including a plus score against his friend, Tal. He was also a five-time Russian champion (this title predates the Soviet Union, and is not the same as champion of the Soviet Union).

I was a Russian linguist in the Air Force during the cold war (1980-1988), and all of my Russian teachers were “off the boat” as they say, meaning they were natives of the Soviet Union, so we heard many stories about life there, and Nezhmetdinov’s story is not uncommon: Lack of favor.

During his peak years, Nezhmetdinov only managed to play outside of the Soviet Union one time, and he finished second to Korchnoi at Bucharest 1954, which again showed that he was strong enough to be a GM. Unfortunately, strength is not the only factor in getting a title. FIDE has long had in place title rules that were designed to make sure that federations could not manipulate titles, thus you have to play x-number of other titled players, and x-number of players from other countries. So, back then, it was harder to get titles because there were not as many titled players as there are today.

Typically, in the Soviet Union, there were also “favorites”, and they were people, who were Communist Party members, or related to those, who were. If you were not a favorite, you could not travel abroad freely as you can today, and they lived behind what was called “The Iron Curtain”. The Party also worried a lot about players defecting, so in essence, your whole country was a prison of sorts. There were exceptions, who were not Party members, but who were so talented that they could bring the Party great favor and prestige, especially when it made the West look bad. Nevertheless, I read somewhere that Nezhmetdinov was a low-level party member, but he was also not a prodigy as were the Tals and Spasskys of the time.  As great as Rashid Nezhmetdinov was, he had huge flaws in his game, and thus, he would probably never become World Champion, and the top chess players knew it, and thus, the Party did not favor him. If you were not given the opportunity, you cannot succeed. He was also an ethnic minority, a Tatar, which also surely played a role in this.

Personally, I would love it if FIDE would posthumously award Nezhmetdinov the Grandmaster title. He is easily the best player ever not to get the title, during the era of titles. I have since written an email to FIDE President, Arkady Dvorkovich, regarding the possibility of posthumously awarding Rashid Nezhmetdinov the GM title.

For anyone, who does not know of Super Nezh, I suggest you search for some of his games. He has what might be the greatest queen sacrifice ever.

I was asked in comments why black resigned after 33. Ke2, so I added a sample line just showing where to put the white pieces, and how that will eventually lead to an easy win, and Chernikov knew it.

 [Event "Rostov on Don"]
 [Site "Rostov on Don"]
 [Date "1962.??.??"]
 [Round "?"]
 [White "Nezhmetdinov, Rashid"]
 [Black "Chernikov, Oleg L"]
 [Result "1-0"]
 [ECO "B35"]
 [PlyCount "65"]
 [EventDate "1962.??.??"]
 [EventType "game"]
 [EventRounds "1"]
 [EventCountry "URS"]
 [FEN ""]

 1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 g6 5. Nc3 Bg7 6. Be3 Nf6 7. Bc4 O-O 8. Bb3 Ng4 9. Qxg4 Nxd4 10. Qh4 Qa5 11. O-O Bf6 12. Qxf6 Ne2+ 13. Nxe2 exf6 14. Nc3 Re8 15. Nd5 Re6 16. Bd4 Kg7 17. Rad1 d6 18. Rd3 Bd7 19. Rf3 Bb5 20. Bc3 Qd8 21. Nxf6 Be2 22. Nxh7+ Kg8 23. Rh3 Re5 24. f4 Bxf1 25. Kxf1 Rc8 26. Bd4 b5 27. Ng5 Rc7 28. Bxf7+ Rxf7 29. Rh8+ Kxh8 30. Nxf7+ Kh7 31. Nxd8 Rxe4 32. Nc6 Rxf4+ 33. Ke2 (33. Ke2 a6 34. c3 Rf7 35. Nb4 a5 36. Nc6 a4 37. a3 Kg8 38. Be3 Kf8 39. Nd4 Rb7 40. h4 Ke7 41. Bf4 d5 42. g3 Kf6 43. Kd3 Rb6 44. Bg5+ Ke5 45. Nf3+ Ke6 46. Kd4 Rb8 47. Ne5 Rg8 48. Bf4+- {and Kc5 next wins}) 1-0


What is meant by "nerves" in chess? It is said about chess players in general. For example, Wikipedia says about Ivanchuk:

  His inability to become World Champion despite his immense talent and longevity among the chess elite has been attributed to his admittedly poor nerves, which were exposed during the high-tension atmosphere of World Championship match-format tournaments

What does this "poor nerves" mean? Does this mean he cannot cope up with the stress?

Yes to both questions.

At the highest level of any sport/game/activity, there is an extreme amount of pressure.  Being in a foreign city, the quest to find the best move, the knowledge that most chess players will be going over you game, annotators criticizing your every move, and the added pressure of a ticking clock.  (Digital clocks don't tick, but most chess players prefer this reference.)  Professional chess players have been known to lose 20 pounds(9 kg) during a normal 2 week tournament, due to the stress of the situation.  Although I don't think they consider this, one misplay and they will be remembered like Bill Buckner.


Trompowsky: why does 1.d4 Nf6 2.Bg5 d5 3.e3 e6 score so highly for white in master games? I'm trying to find a suitable response to the Trompowsky using LiChess.  I saw the following line, which looks like it might transpose into more familiar QGD territory.

[fen ""]
1.d4 Nf6 2.Bg5 d5 3.e3 e6

On LiChess, in master games, white scores 52% wins, 33% draws, and 15% losses.  It seems black's moves are faulty for some reason.  I'm not sure why though---it looks like white has a sharp line.

For contrast, after 3...c5 white scores 24% wins, 48% draws, and 29% losses.  So 3...e6 scores significantly worse.

Question: Why does 1.d4 Nf6 2.Bg5 d5 3.e3 e6 score so highly for white in master games?

3..e6 closes the way for your light-squared bishop, but I don't think that's too good of a reason to reach such scores (I checked on ChessTempo and got similar numbers)

Please be careful about possible bias due to player strength differences. A move may score worse simply because it is often used as a "drawish weapon" against a stronger player. This is the case of the French exchange variation, where Black scores better in a symmetrical position! But there could be other reasons why an opening system is more common among weaker players

I would tend towards an explanation of this kind, since there does not seem to be a clear "refutation" in the position you show (4.c4, 4.Nd2, 4.c3 and 4.Nf3 all score similarly.

Please specify your own skill level for further advice on how to build a repertoire around these lines to be possible


Chessbase vs Hiarcs for DB management I am a Mac user and ChessBase is not available. Instead I purchased Hiarcs. I would like advise as to whether there's added value to ChessBase that should motivate me to install ChessBase on Parallels or even to buy a cheap laptop for this.
Note: my question is not related to engine usage as I don't believe that should matter so much, but rather for DB management, meaning availability of DBs, ease of management, etc... Any pointers would be appreciated!

By far, ChessBase is the most popular one, it has been there for a long time. But there is other software that can do more or less what ChessBase can do, like Chess Assistant.

When you compare software, you should consider comparing for example Fritz vs. Hiarcs or ChessBase vs. Chess Assistant, because Fritz or Houdini or Rybka are mainly engines with the capability of full game analysis and ChessBase is more of a database with special feature for the pros.

In terms of opening encyclopedia or other products, they could be read with almost any professional chess software. So, no problem here.

Finally, if you are not a professional chess player, any software like Hiarcs, Shredder or even Stockfish with a GUI could help you and you don't need to buy such expensive software.


How to generate hash keys for chess positions Is there a standardized method for generation of hash keys for chess positions. I want to implement hash key generation in my program, so wanted to know the best way to do it.
It would be great if someone can provide details on how the opening books do their hashing (.bin?).

Thanks!

I believe you're talking about Zobrist Hashing.

  a technique to transform a board position of arbitrary size into a number of a set length, with an equal distribution over all possible numbers

https://chessprogramming.wikispaces.com/Zobrist+Hashing

Why Zobrist?

Rather than computing the hash for the entire board every time, the hash value of a board can be updated simply by XORing out the bitstring(s) for positions that have changed. That makes the hashing algorithm very efficient for chess engines.


Unlearning myths from the mind of an experienced club player I recently met a club player who had been playing chess for 23 years, but couldn't improve his ELO more that 1800. When I played with him, I found his tactical skills are good, moderate endgame knowledge (excels in rook endgames) and poor opening knowledge. Afterwards we had a chat and I could uncover several myths in his mind such as knights are superior to bishops, two rooks will never beat a queen etc.
If I am tutoring a student like him, how would I go about teaching him.
My first impression is to make him unlearn the 'myths' in his mind, teach a few opening lines helping him to understand basic principles like developing pieces quickly, controlling the center etc.

Teach him by showing example positions that you can play out against each other. There is a big difference between being told that two rooks are often stronger than a queen and really experiencing the power of the two rooks. You could maybe play out a position from the Kramnik-Leko match 2004.


How do you solve chess tactics? Do you just grind them, or do you save some of the chess tactics that you miss?

Do you ever annotate your chess tactics?

Do you try to remember certain patterns and main ideas? Do you categorize your tactics by forks, pins, zugzwang, etc.?

How do you recommend we train tactics puzzles?

Training chess tactics should be done by theme. This means solve a set of tactics that are based on a similar theme, like Double Attack, Discovered Check, Absolute Pin, Relative Pin, Skewers, etc. This impresses upon the mind the ideas of that particular kind of tactic and gets your brain looking for it as a matter of course. After, you will find yourself 'seeing' these tactics (i.e., imagining) in your games or at least considering them as a means to an end in your positions. This is the creativity you cultivate in your chess game.


What influenced the development of the King's Indian Defense? The King's Indian Defense is characterized by the moves 1. d4 Nf6 2.c4 g6. (As opposed to 2. . .e6, with the intention of developing the Bishop to the Queen-side.) Black aims for a strong King-side offense with sharp tactical play. The Classical line:

[FEN ""]
1. d4 Nf6 2. c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 O-O 6.Be2 e5

Nimzowitsch and others of the hypermodern school popularized the Nimzo-Indian and Queen's Indian defenses eary in the 20th Century. The King's Indian was known, but was seen far less frequently until David Bronstein started playing it in the 1940s and 50s.

So, to the question, what factors brought the King's Indian to prominence aside from Bronstein? What developments in theory advanced its use compared to the other Indian defenses?

(To clarify: I'm coming at this as someone who's unrated and no more than a casual player at best. I'm looking more here for the historical aspects and understanding of the times, though I won't turn down discussion of modern theory.

Additionally, I'm aware that this is subjective. I'm fairly confident it fits into "good-subjective", given the nature of Chess.SE. There hasn't been any major discussion on the KID here, and I'd like to see what the minds here have to say about it, given how important it is in modern play.)

In all the Indian Defenses, in general, Black allows White to occupy the centre with his pawns.

Nonetheless, in Nimzo-Indian and Queen's Indian Defense Black has many moves to attack White's pawn centre very early in the game, thus White cannot gain too much space.

King's Indian Defense (and Gruenfeld Defense), on the other side, really do not care that much for the first 4-5 moves of White, so that he can occupy the centre with an "horde" of pawns (see for example the Classical Variation, the Saemisch Variation or the Four Pawns Attack), with a huge advantage of space.

Since hypermodern principles in chess were born only in early 20th century, they were not universally accepted before '40s. And having such a big space disadvantage in the opening was seen with suspect (if not explicitly considered "strategically losing"). That's why, in my opinion, KID had to wait to be considered consistent enough to be played regularly by top players.


Most Gambits Declined in a Single Game Bit of an odd question that has arisen from a game that I played today. In the game it started of with the Queens Gambit (which appear to be the flavour of the month due to Netflix). I usually dont enjoy playing into it and ended up playing the Albin Counter Gambit (e5). In the first time in approximately 60 odd games of it, my counter gambit was declined.
[Event "How many Gambits?"]
[White "Random Hero"]
[Black "Yours Truly"]
[Result "*"]
[PlyCount "5"]
[FEN ""]

1. d4 d5 2. c4 {Queens Gambit, accepting is taking the c4 pawn} e5 {Queens Gambit: Declined Albin Counter Gambit} 3. Nc3 {Albin Counter Gambit Declined. Accepted Line is usually dxe5} Bb4

This got me thinking. How many gambits can exist in a single game? I know in this instance 2 but I can't think of any other examples that have a 3rd Counter Gambit. Be curious if anyone knows of any other examples.
Most recent Master Game I can find with this position Azmaiparashvili vs Kanep (2006) which probably indicates its not the most sound theory.

I have a sequence of four gambits. Starting with Bird's Opening: 1. f4:

1... e5 offers the From's Gambit
2. e4 offers the King's Gambit
2... d5 offers the Falkbeer Counter-gambit
3. d4 offers the Hinrichsen Gambit

And Black declines the last gambit with 3... Nf6.
[FEN ""]

1. f4 e5 2. e4 d5 3. d4 Nf6


Do chess masters think with the board flipped when playing black? Or do they always keep white on the bottom, as is the case with most historic games? Wouldn't it be easier for them to spot patterns from old games if they always oriented the board the same way in their minds?

In Blindfold Chess (Hearst-Knott; reviewed and summarized here), a natural beginning place for studying the thought processes of chess masters, the authors discover this (quote from the link):

  blindfold chess masters consistently report that what they visualize are not images of pieces or chessboards, but abstractions of these with minimal or no physical features.

And later, they describe their mental state in a variety of telling ways:

  “no mental pictures,” “abstract knowledge,” “I know where the pieces are,” “only an abstract type of representation,” “only relationships,” “no real picture,” “the significance of a piece,” “knowing what combination or plan is in progress,” “lines of force,” “pieces are only friend or foe, carriers of particular actions,” “sort of formless visions of the positions,” and so forth. Many of the masters report that they have no mental image at all (p.151).

This suggests that your question is actually based on a faulty premise: that chess masters explicitly visualize a board while contemplating a position. Instead of colored pieces "visualized" on a board, they seem likely to think about the position in a more abstract fashion.

The source covers blindfold chess, naturally, but I would be astonished if the same concepts were not true for most masters in general.

I'm not master level myself, but for what it's worth, I would also describe my mentalization process in similar, abstract terms. I almost never "picture" the board.


What exactly means centipawns field in stockfish/uci output? According to this page:

cp
        the score from the engine's point of view in centipawns.

but is it a score for the current (start) position of the game that I feed to engine, or it is a difference between start and final(when coputations completed and best line found) scores?

And the range in which this value varies is unclear to - how could it be as big as 6000 that I sometimes get for my positions? That would be a ton of figures:)

It's the score of the current position, but it is computed by static evaluation (i.e. counting pieces, pawns, pawn structure, king safety, mobility, etc.) of positions arising in the program's search tree, and applying the minimax algorithm and alpha-beta pruning.

A cp-score of 6000 does indeed mean the engine thinks White is 60 pawns (centi means 1/100) = between 6 and 7 queens ahead. Because it wasn't able to find a forced mate, it will just try to get the highest possible point advantage, knowing that this will bring the game closer to mate. In practice, a score of (+/-)150 is already decisive most of the times.


Stockfish 6 in Chessmaster Grandmaster Edition Is their a way to install stockfish 6 in Chessmaster Grandmaster Edition ?

To use stockfish, you need GUI that supports UCI. I can suggest Arena or Scid vs. PC as good free GUIs.
Chessmaster isn't capable of that.


Why did Kung Fu Chess shut down? Kung Fu Chess, a chess variant in which there are no turns (everyone can move at once with a time delay for each piece), began in 2002 by Shizmoo games, and the website suddenly went offline in 2008 despite a large following and many proficient players.

Is the reason for their sudden demise known and are there present day alternatives to kung fu chess?

No reason for Shizmoo's site closure in 2008 has been published online that I could find. There is a forum for former Kung Fu Chess enthusiasts here, but it's not particularly busy at the moment: http://www.zenchess.com/forum/

A few turnless/live chess variations inspired by Kung Fu Chess have sprung up, though, notably:

Ninja Chess for iPad

http://www.nordlysa.com/ninjachess/

Two players, iOS.

Real Time Chess

http://play.svenardo.com/chess/

One-player vs computer, in-browser, iPad, Mac and Windows, where the first player to capture the king wins. Moved pieces cannot be moved again until their timer completes.

JebChess

http://jebchess.com/

A four-player live version.


Why does Stockfish give a negative score in a theoretical win for white? 8/3k4/8/3K4/3P4/8/8/8 b - - 0 1

(Black to move)

This is a theoretical win since White has the opposition and the king is in front of the pawn.

I have downloaded the Windows version for Stockfish 9 and followed the UCI protocol.

Stockfish:

Stockfish 9 64 by T. Romstad, M. Costalba, J. Kiiski, G. Linscott

Input:

uci

Stockfish:

id name Stockfish 9 64
id author T. Romstad, M. Costalba, J. Kiiski, G. Linscott

option name Debug Log File type string default
option name Contempt type spin default 20 min -100 max 100
option name Threads type spin default 1 min 1 max 512
option name Hash type spin default 16 min 1 max 131072
option name Clear Hash type button
option name Ponder type check default false
option name MultiPV type spin default 1 min 1 max 500
option name Skill Level type spin default 20 min 0 max 20
option name Move Overhead type spin default 30 min 0 max 5000
option name Minimum Thinking Time type spin default 20 min 0 max 5000
option name Slow Mover type spin default 89 min 10 max 1000
option name nodestime type spin default 0 min 0 max 10000
option name UCI_Chess960 type check default false
option name SyzygyPath type string default <empty>
option name SyzygyProbeDepth type spin default 1 min 1 max 100
option name Syzygy50MoveRule type check default true
option name SyzygyProbeLimit type spin default 6 min 0 max 6
uciok

Input:

position fen 8/3k4/8/3K4/3P4/8/8/8 b - - 0 1
go depth 1

Stockfish:

info depth 1 seldepth 1 multipv 1 score cp -4276 nodes 5 nps 2500 tbhits 0 time 2 pv d7e8
bestmove d7e8

Why is the evaluation -4276?

Because Black is to move, and for Black the position is evaluated as being 42.76 pawns behind.


My bottle of water accidentally fell and dropped some pieces. Now what? While playing a rapid game, I accidentally dropped my water bottle on the chessboard, which made many pieces fall. I don't remember the initial position, and neither does my opponent. Should we play the game again, or is there any other rule about such cases?

There are two articles in the FIDE Laws of Chess which cover this, 7.4 and 7.1.

7.4.1 If a player displaces one or more pieces, he shall re-establish the correct position in his own time.
7.4.2 If necessary, either the player or his opponent shall stop the chessclock and ask for the arbiter’s assistance.
7.4.3 The arbiter may penalise the player who displaced the pieces.

So, first of all you should expect some kind of time penalty for what you did. Note that it doesn't make much difference that it wasn't your fault in the sense that you may not have done it deliberately.
Playing in a tournament some years ago I saw something similar happen. One player stood up and his leg caught the tablecloth pulling it, displacing a glass of water and the board which also got soaked. The arbiter came running over and the first thing he did was add two minutes to the opponent's time because of the disturbance caused. This was at standard time controls so the moves were recorded but in any case both players were of a sufficient level to be able to recall the position exactly.

7.1   If an irregularity occurs and the pieces have to be restored to a previous position, the arbiter shall use his best judgement to determine the times to be shown on the chessclock. This includes the right not to change the clock times. He shall also, if necessary, adjust the clock’s move-counter.

So, if neither of you can recall the exact position immediately prior to your accident then you should try and agree on a previous position. Unless you are both complete beginners you are likely to at least remember the opening.


Is it permitted to stare at a blank chessboard during a tournament game? Long-winded Motivation

I have recently noticed during my own tournament games that I am not infrequently closing my eyes, or at least looking away from the board, when engaged in in-depth calculation (or what counts as in-depth for me). This isn't deliberate on my part; it's just something I've naturally started doing more often. I know that some well-known players do this quite a lot, e.g. Ivanchuk has a reputation of very often staring up at the ceiling when calculating, and I think it actually makes a good deal of sense:

  Having an image of the current position in front of you can be helpful if you're apt to lose track of it. But that's not a problem for someone like Ivanchuk, and so that "plus" is inconsequential. On the other hand, having the full current position right in your visual field might actually interfere (for some folks) with the process of fixing projected future positions in your mind's eye, thus sometimes leading one to look away.

With that in mind, it seems not unreasonable to me that a lesser light than Ivanchuk might possibly benefit from the middle ground of staring at a blank chessboard while calculating like this. The current piece positions aren't there to interfere, while one still gets the image of the chessboard to serve as a potentially useful "frame" for the successful mental imaging of positions. I don't think that I'd actually find it very useful, and perhaps nobody would, but that's neither here nor there as far as my question is concerned.

Question

  While one obviously can't use an analysis board when playing tournament chess, do the rules (e.g. FIDE or USCF) actually preclude having an empty chessboard nearby at which to stare while calculating?

Many scorebooks already have scoresheets that look something like this:

Thus many tournament players already have a small empty board available to use exactly as I've described, if they so desired. So, is it technically permissible for them to place an empty board nearby before the game, and stare at it if they like? (If nothing else, I suppose one could make custom scoresheets featuring quite large empty diagrams ...)

FIDE rules 12.3a and 6.14 are relevant to this situation. The former rule is vague, but the latter strongly suggests it is allowed. Let's take a look.

Rule 12.3a

  12.3a    During play the players are forbidden to make use of any notes, sources of information or advice, or analyse on another
  chessboard.

This rule does not define the word analyse, and hence, the verdict would depend on whether "staring at blank chessboard" constitutes analysis.

Rule 6.14

  6.14 Screens, monitors, or demonstration boards showing the current position on the chessboard, the moves and the number of moves made,
  and clocks which also show the number of moves, are allowed in the
  playing hall. However, the player may not make a claim relying solely
  on information shown in this manner.

Since a board showing current position is allowed, it is strongly implied (though not explicitly stated) that looking at a blank chessboard is allowed.

Used rulebook on the FIDE website here.


Do Chess Engines hold their Search Tree in Memory? Does a typical brute-force chess engine (e.g. Stockfish) hold its search tree in memory as it applies iterative deepening? If so how does it avoid running out of space? And if not, how does it store the results from each depth before it searches the next ply? It is my understanding that the evaluations from each depth are used to order the possible moves for the next depth, but where are these evaluations and their associated positions stored?
Also, do engines save the pseudo-legal moves they generate for each position, or do they re-run the move generation function each iteration of the search?

A traditional engine does not hold its entire tree in memory. E.g. Stockfish on a 6 core machine can search maybe ten million positions per second. Even if you could store a tree node in just 8 Bytes, that would take 80 MB per second searched. So an hour long search would need hundreds of gigabytes. Instead one uses so called transposition table where the evaluations for certain positions can be stored. Then if a research at a higher depth hits that position again one may already have a sufficiently deep evaluation.
Obviously the same problem applies, a transposition table won't be big enough to store all positions. Because of that, a new transposition table entry may overwrite an existing entry if no memory is free anymore. That loses the old information, however that is not avoidable one way or another.
Note that an engine like Leela has a much lower node per second speed. Because of that for it storing the entire tree is possible (and in fact necessary for the PUCT based search that it uses). Even then you can still eventually run out of memory, one way to combat that in practice is the use of a swap file to store a tree larger than your memory. But if that file fills up to then you can't search further.
As for move generation, for engines that don't store the tree, like Stockfish, one indeed has to re-do the move generation at each point. However that's not much of a problem as a good move generator is very fast so it won't take a lot of time.


Website or program that creates puzzles from blunders in your past games I'm looking for a website or program that would look at your past games on Lichess or chess.com and find moves that you played that were blunders and create puzzles around those

I don't know of a single program that does all that. I do it myself with following steps. I save most of my games in a pgn file. The interesting ones, esp. my losses, are analyzed by Stockfish. The "blunder threshold" is your choice, typically 3 - 5 pawns or more. With Notepad++ text editor I enter the FEN of the position in a pgn file, of course preceded by the tag line [SetUp "1"]. Answer is best line of Stockfish. I skip positions that are cooked by good alternative choices.
When 50 - 100 puzzle positions are accumulated I transfer the pgn file to my Android phone & tablet. I display them with iChess but many other apps handle pgn files.


Tips for debugging and progressing a chess engine's implementation As I mentioned in previous questions I'm currently following this tutorial for building my chess engine.

The code was written in C#, but mine is in C++ and I'm in  the phase of finalizing the board / piece / moves / valid moves representations without testing the logic just making sure the syntax is ok.

So I'm confused as to what should I do now, just continue writing without testing or there is a good way to test an incomplete chess engine?

Here you can take look at what I have done so far and your comments / recommendations are appreciated

I glanced at your code:

You should test your code with perft. Google it if you're not sure what it is.
Please make sure your code works before coding the engine search. If you unable to generate moves properly, nothing in your search will work.
Consider to use an array rather than a switch statement for piece values.
Consider to code your squares as an integer, not as a C++ class
Consider to collapse your WHITE and BLACK implementation together. C++ template would do that for you. Please take a look at Stockfish codebase if you're unsure.
I don't see you're making en passant in the code. Are you sure you have that covered?


Where I can download images of chess pieces for my chess app? I am developing an Android app and I need chess pieces images for my it. I am concerned about copyright issues as well. I can copy images from other chess apps on GitHub projects, but I am not sure if that is legal. Is there any free source to get images of chess pieces?

Check out the licenses of the piece sets that lichess uses: https://github.com/ornicar/lila/blob/master/COPYING.md#exceptions-free
Personally I am using the cburnett piece set for my project.


endgame with single Bishop or single Knight? If given the choice should I opt for an endgame with a single Bishop or a single Knight? I understand Bishops increase in value in the endgame but is the disadvantage of covering only half the squares really compensated by increased mobility?

Please consider the below possibilities (with Kings naturally always present and a couple of pawns in each case):

Bishop -vs- Knight
Bishop and Knight -vs- two Knights
Rook and Bishop -vs- Rook and Knight
Queen and Bishop -vs- Queen and Knight

My feeling is that in all cases except 1, the Bishop option is better (since the other piece covers the whole board). I known that Capablanca was of a different opinion but I've read that this has not been validated empirically, at least in a statistically significant way.

If given the choice should I opt for an endgame with a single Bishop or a single Knight?

In order to properly answer this question I must point out differences between bishop and knight:

Bishop is a faster piece and has a longer range of fire, but can cover only half of the board.
Knight on the other hand, is a slow and clumsy piece but covers squares of both colors. When I say clumsy, I am referring about knight's difficulty to position himself fast to the nearby square. Another problem with the knight is that he can not make a move and keep previous square under control which disables him from making zugzwang. For examples of what I have stated here please read my answer to this question. I believe those diagrams demonstrated well my statements.

I will quote highly instructive excerpt from the book Steve Mayer-Bishop versus Knight the Verdict ( but this regards superiority of bishop pair over 2 knights/ knight+bishop ) :

In contrast to the far-reaching bishop, which can become effective from distance, the knight, in order to become effective, has to operate in close proximity to the opposing forces. In order to become lastingly effective, it must find protected squares near the enemy's camp, mostly squares protected by pawns, in asmuch as other pieces are in the long run not suitable for the protection of the knight. It follows therefore that in completely open positions without pawns, the bishop is superior to the knight, a fact that is confirmed by the results of the endgame theory. Conversely, the knight is superior to the bishop in closed positions, on the one hand because the pawns are in the bishop's way, and on the other hand because the pawns form points of support for the knight, as remarked above.

Now is the time to address the actual questions:

  Please consider the below possibilities (with Kings naturally always present and a couple
  of pawns in each case):

  Bishop -vs- Knight
  Bishop and Knight -vs- two Knights
  Rook and Bishop -vs- Rook and Knight
  Queen and Bishop -vs- Queen and Knight

1. Bishop -vs- Knight

As stated above, pawn structure and king's position has a paramount importance.

If there are pawns on both sides of the board and position is relatively open then bishop is usually the better choice. This is especially true if both sides can make a passed pawn since bishop can use his speed and long range to stop/slow down opposing passed pawn while helping his own to advance. Furthermore, if the position is open bishop/king can easily harass the knight forcing him to abandon the control of the key squares due to his short range.

Since this will be a long post let us take a break and enjoy in following demonstration of bishop's superiority in open positions with pawns on both sides:

[StartFlipped "0"]
[White "Stoltz"]
[Black "Kashdan"]
[Event "Hague Olympiad,1928"]
[fen "6k1/p2b1ppp/8/8/3N4/1P5P/5PP1/6K1 b - - 0 1"]

1...Kf8 2.Kf1 Ke7 3.Ke2 Kd6 4.Kd3 Kd5 5.h4 Bc8! 6.Nf3 Ba6+ 7.Kc3 h6 8.Nd4 g6 9.Nc2 Ke4 10.Ne3 f5! 11.Kd2 f4 12.Ng4 h5! 13.Nf6+ Kf5 14.Nd7 Bc8 15.Nf8 g5 16.g3 gxh4 17.gxh4 Kg4 18.Ng6 Bf5 19.Ne7 Be6 20.b4 Kxh4 21.Kd3 Kg4 22.Ke4 h4 23.Nc6 Bf5+! 24.Kd5 f3!-+ 25.b5 h3 26.Nxa7 h2 27.b6 h1=Q 0-1

Notice how Black used his bishop to create zugzwang with 5...Bc8!. That is something knight can not do->bishop moved to c8 and kept f5 square under control. This resulted in White king being forced to allow opposing king to penetrate. This is usual motif in this type of ending. Side with the bishop uses zugzwang to penetrate with the king. Next, notice how Black played 7...h6, 8...g6 and 10.f5! to undermine knight's position. This game well illustrates what quotes from Steve Mayer's book about knight needing stable pawn support in order to be permanently effective. Finally, notice how knight was too slow to position himself properly for stopping the passed pawn after 13.Nf6+.

Here is an example of bishop overpowering knight when both sides have passed pawns and position is open:

[Title "Liverpool-Glasgow, correspondence"]
[fen "8/2n5/5k1p/P1p4P/4K1B1/8/8/8 w - - 0 1"]

1.Be2 Ke6 2.Bc4+! Kd6 3.Kf5 Nd5 4.Kg6 Ne3 5.Be2 c4 6.Kxh6 c3 7.Bd3 Ng4+ ( 7...c2 8.Bxc2 Nxc2 9.Kg6 Nd4 10.Kf6! Ne6 11.a6!+- ) 8.Kg5 Ne5 9.Bc2 Nc4 10.a6 1-0

An important weapon when fighting with bishop against the knight is "domination" and is demonstrated below:

[Title "Bishop dominates the knight"]
[fen "K1k5/8/8/8/2B5/8/8/2n5 w - - 0 1"]

Here is another example where bishop overpowers the knight when pawns are on both wings using "domination":

[White "Goldberg"]
[Black "Tolush"]
[Event "Moscow, 1949"]
[fen "8/pk3p1B/1p1p1P2/2pP2p1/2n5/P1P3P1/7P/4K3 w - - 0 1"]

1.h4! gxh4 2.gxh4 Ne5 3.Bf5! Nf3+ 4.Kf2 Nxh4 5.Be4!+- Kc7 6.Kg3 Ng6 7.Bxg6 fxg6 8.f7 1-0

In open games with pawns on both sides bishop is almost always to be preferred than a knight. This is the case with 90% of endgames. I know others will disagree, but I state this based on my experience and experience from analyzing grandmaster games: Always prefer bishop than a knight in the endgame. Why? Knight is better than a bishop only if the side with the bishop has severe defects in its position and no counterplay whatsoever. I have never seen practical position from a grandmaster game where knight dominated the bishop after both sides played reasonably well. As stated in the quote above from Steve Mayer's book, knight needs secure strongpoint and must be in close proximity of the opponent in order to be efficient. Also, the oposing bishop must be restricted which requires a lot of pawns on the board which is not characteristic for the endgame. To prove my point I am choosing an example where side with the "bad bishop" and isolated pawn manages to hold a draw:

[White "Flohr"]
[Black "Capablanca"]
[Event "Moscow, 1935"]
[fen "8/1p2kppp/p3b3/3p4/3N4/4P3/PP3PPP/2K5 w - - 0 1"]

1.Kd2 Kd6 2.Kc3 b6 3.f4 Bd7 4.Nf3 f6 5.Kd4 a5 6.Nd2 Bc8 7.Nb1 Be6 8.Nc3 Kc6 9.a3 h6 10.g3 h5 11.b4 axb4 12.axb4 Kd6 13.b5 g6 14.Na4 Kc7 15.Nc3 Kd6 16.f5 gxf5 17.Ne2 Bd7 18.Nf4 Be8 19.Nxd5 Bxb5 20.Nxb6 Bc6 21.Nc4+ Ke6 22.Nb2 Bb5 23.Nd1 Be2 24.Nf2 Bf1 25.Nd3 Bxd3 26.Kxd3 Ke5 27.Ke2 Ke4 28.h3 Kd5 29.Kf3 Ke5 1/2-1/2

This endgame has been heavily analyzed and the last time I checked the verdict was it is a draw. Here White had an advantage and still was unable to win. He had better king, better minor piece and better pawn structure. Still, knight was unable to outmaneuver the bishop because he is slower and "clumsier".

2. Bishop and Knight -vs- two Knights

You need to know rules of the knight endings in order to make the right decision. In a nutshell the side with space advantage usually wins.

The principle in endings with two minor pieces is to exchange opponents most active piece, thus transposing into the favorable endgame. Stronger side avoids pawn exchanges, weaker side strives towards pawn exchanges.

3. Rook and Bishop -vs- Rook and Knight

Heavily favored for the side with the bishop. If you can keep both rooks or both bishops it becomes nearly decisive advantage. For practical example look at Fischer-Tal,Curacao 1962. There are more examples from Fischer's games like Fischer-Petrosian,Candidates match 1971 or Fischer-Taimanov,Candidates Match 1971. Although there were 2 rooks and a bishop it is still good example of how you should play this ending.

4. Queen and Bishop -vs- Queen and Knight

Generally speaking, the advantage goes to the side that can attack opposing king. In practice, side with the knight usually has the advantage. Knight's ability to attack squares of both color is more important here than bishop's speed since queen is so powerful that it can both defend and attack thus giving knight enough time to position itself offensively. Still, I must repeat that all depends on a position and ability to attack opponents king.

If you have questions leave a comment.

Best regards.


Who is the teacher of the game that has a lesson plan as follows: To find the degree (or the number of attacked squares), of a square's corresponding vertex for all pieces and their corresponding graphs, given any square of the board.  In other words, given a piece and a square - the number of attacked squares by the piece at the given square on an empty board is what the student finds.  This is repeated until all squares are examined.

Also, has anyone had the idea to make a 3-D representation for each piece, where each square has a respective height equal to the degree of its' corresponding vertex in the given piece's graph (where the degree is the number of squares attacked by each specific piece at each square)?  Of course, the rook's graph representation would be dull, as the graph is regular (ie the number of attacked squares is the same at any square),  but all the other pieces, save for the pawn, would give students the visual lesson that the pieces in the center have more options.  Not only this, it appeals to an old military adage - to control the high ground - which in these cases is the center, if at all possible.

Not in 3D and not super-fancy, but it should get across the point. I did not do it for the rook because as you note the rook always has 14 squares to go to (on an empty board).

However if you want to use this to argue for putting pieces in the center, I'd be careful, because:

This is for an empty board. Lots of things can happen when other pieces are on the board.
The illustration for the king is probably of limited value because (unless you are Steinitz) we don't usually think of the king as an active piece.
For the queen and bishop (which are essentially the same, only shifted by 14, the number of rook moves) you notice that the difference between different squares (center and border) is not all that great. In my opinion a much more important factor for positioning queen and bishop centrally in a real game is that they have more options, i.e. a bishop in the center can go in four directions while a bishop in the corner has only one direction. This means that a bishop in the center can attack things in all four directions and likewise in order to block this bishop, the opponent has to block four directions. Also for transferring the bishop to other parts of a board a central position might be better.
For the knight there could be some value in this as it cannot be blocked by other pieces, so the situation for a knight is essentially the same as on an empty board. That's where you get the saying: "A Knight on the rim is dim" from. But as with all such rules there are plenty of exceptions.


Who is better in this endgame? This endgame can come out of the scotch gamibt, albeit there are better lines for a black player that desires a draw. However, I was wondering out of curiosity if this is good for white or black.

Komodo 9.3 evaluates the position after 1.Kd5 (after searching to 31 ply) as +2.32 for White. Playing out a few lines, White usually ended up with Q+2P vs Q+P. It's not necessarily winning (Q+P endings have lots of resources for the defender due to all the checks) but I am comfortable asserting that the position is more pleasant for White.

For what it's worth, the position has occurred 6 times in my database, with 4 White wins and 2 draws.


Material for knowing more about Cylinder Chess I love the usual way of playing chess, but I also like a lot Cylinder chess. Does anybody know a book, website or other way of learning more about it? Like maybe a strategy book about cylinder chess or a book about opening theory on it.

There exists several books presenting quickly various variant of chess, here is one example :
http://www.barnesandnoble.com/w/fairy-chess-books-llc/1103593111?ean=9781157372424

About learning strategy or opening theory, both of this concept require a lot of experience and games to be played. For instance in classical chess we had to wait centuries before such thing become available. A first step is to watch games played by the best players. A world championship and tournaments are organized by The Circular Chess Society :
http://www.circularchess.co.uk/

Also, it should be decent training to practice with exercises, many studies has been created with this variant of chess, here is one example :
http://www.mayhematics.com/v/cylin.htm


What does "master" mean? As I read both English and Russian chess literature I run into the term 'master'. It is clear from the context that is below grandmaster but is somehow given much respect. I never know what it actually means because it could be any of the three or even something else: FIDE Master, International Master, National Master (whose meaning depends on the country).

This site has many questions about 'master strength' so it is part of everybody's jargon. But I really don't know what it means.

There are several reasons why someone would use the term 'master', but without a specific reference to work from all I can suggest is that the term is generally synonymous with the phrase 'top player'. The two examples that come to mind are:

Historical: Many of the great early players did not have actual titles (either because the titles had not been invented or because the systems for reliably attaining them had not been introduced). In this case, one might refer to Morphy or Philidor as a 'master', simply because calling them a GM/IM would be inaccurate. Also consider that when the title 'Grand Master' was first conferred, it was not just a title to hand out to players but a real statement that those five players were some of the best ever.
Cultural: As you noted in the question, many foreign (esp. Russian) books up until the 1980s or so use the term. I cannot say exactly why, but the usage is certainly meant to indicate that those people are deserving of respect as top-calibre players. Perhaps part of this is due to the fact that some top theoreticians were not acknowledged as being among the best practical players, and so this allowed them to be given the same level of respect as determined by the author. Hopefully someone more knowledgable in soviet chess culture can fill us in on this one.

This is in contrast to the modern USCF system where a range of various master titles are (by comparison to earlier times and other areas of the world) given out like candy. This is not to say that the achievements are not still somewhat impressive, but they ultimately mean something much less than the term does in those other contexts.


Where can I find the live standings of the Grand Chess Tour? The final stage of the Grand Chess Tour is being held these days at London and I was wondering who's going to win the general prize of the series.

In the official website I could just find the standings after the Sinquefield cup, but I couldn't find the live standings updated after each game. I know that I can calculate them by hand, but I'd like to find a website with them.

Where can I find the live standings of the Grand Chess Tour?

On the London Chess Classics website, there is a link to the GCT Estimated Standings

An estimate is the best you can get though:

  ... The points actually allocated will be determined by tiebreaks which cannot be calculated until the end of the tournament...


Is there a data file available (e.g. a .csv) containing every single rated game? Question
Is there a data file somewhere containing every single (FIDE) rated game?
What I found out so far
I see many websites with some limited database search capability, or summary statistics, but I couldn't find anywhere to simply download a complete dataset of FIDE games.
Such a dataset would have each row being a new game, and would hopefully also contain who played, who won, when it was played, and other info.
(Very) Rough size estimate
I estimate such a file would be quite large, which I base of some extremely rough estimates

How many FIDE players? (probably) tens of thousands
How many games on average per year? Probably hundreds
Therefore 10000 * 500 = 5m games per year
5m games per year * about 100 years comes to about 500m rows

If each row is approximately 1kb, the total file size (uncompressed) would be: half a terabyte!
But still, tools like spark or bigquery could easily handle this, and it would be fun to analyse if it is available somewhere in its entirety.

Is there a data file somewhere containing every single (FIDE) rated
game?

As an arbiter I can tell you definitively that the answer is "No". However you don't need to be an arbiter to know that. You just need to have played in a FIDE rated blitz tournament. Nobody is writing the moves down in those tournaments.
In FIDE rapid tournaments you do get a few players who start out recording but many of them stop when they get short of time and those games don't end up in databases.
Even when it comes to standard time control FIDE rated games only those games played in norm events have to be sent to FIDE (to make sure there is no cheating to get titles like GM and IM). So, all games played in norm events should be recorded and sent to FIDE. For each such tournament the games should be available for download from the FIDE site and those games will be picked up by the spiders / web-crawlers used by the big database providers.
However the large majority of FIDE rated standard games are not played in norm events and so there is no requirement for arbiters and organizers to send those games to FIDE. Doing so is hard (unpaid) work and so most arbiters and organizers are not going to do it.


Is there an online chess game or app that allows for custom setup of pieces and printing this setup? I want to setup positions for my grandsons to show different tactics and print them. Lichess is excellent except that it won't print the pieces on the board. Any suggestions?

If you are using Windows, the easiest way may just to set up the position you want on lichess.org, and use the Windows "Snipping Tool" to grab, and print, whatever part of the screen that you want.

This is not a tactic, but that is what I just did here:


Why is ...d5 the best move for Black? I am learning chess and came across this position. Stockfish 11+ HCE (Depth 32/99) and Stockfish 13 (Depth 31/47) both says ...d5 is the best move for Black. But the next move is exd6 e.p., leaving White's pawn at d6, defended by the e4-Knight and Queen, so Black cannot recapture it immediately with Bxd6.
Following along with the engine, Black doesn't really attacks the d6-pawn until at least 10+ moves later. So why did the engine suggest Black sacrifice the only central pawn it has for no apparent reason (at least to me)?
[FEN "r1bqkbnr/pp1p2pp/8/1p2P3/4N3/8/PPP2PPP/R1BQK2R b KQkq - 0 8"]
1. e4 e5 2. Nf3 Nc6 3. Bb5 f5 4. d4 fxe4 5. Nxe5 Nxe5 6. dxe5 c6 7. Nc3 cxb5 8. Nxe4

10+ moves later is enough! Note that material-wise, Black is already winning. The sacrifice Nc3 is far too speculative. What is the worst thing that could happen to Black? Nd6+, walling him in, or even followed by some Re1+ after exchange on d6. Thus, rather sacrifice a pawn while White hasn't even castled, than allow any swindles.


On how old hardware can modern engines be run, and how strong are they? For example, could modern Stockfish theoretically, with the hardware at the time, be entered into the 1974 World Computer Chess Championship?  If so, would it be grandmaster level?

could modern Stockfish theoretically, with the hardware at the time,
  be entered into the 1974 World Computer Chess Championship?

No. Modern Stockfish is not compatible with 1974 computer architecture.

Modern engines which can run on 64-bit Linux should be able to run on an early 90's Digital Equipment Corporation 64 bit Alpha PC running Unix with a suitable recompile and perhaps tweak of the code.


Moving a game up or down the SCID database list? Is there a way to move an individual game up or down the database list? Or give it a new game number in the list?

SCID orders the items in the order that imported them. You can modify the sort order in the list of games. Click in the column names to change the sort order or to reset the sort. But you can't change the individual position of a game in the list.

And what columns can be shown, seems to be hard coded. But if you add a collection of games that are numbered, say on the event tag, it is possible to sort that database by that tag.


Testing an engine (UCI) against an older version of itself I am making modifications to a chess engine.

I want to get quick feedback on whether the modified version seems stronger than an unmodified version or not, by fighting the older version multiple times.

Does anyone know about a good tool to do this? (Currently I have some homemade code to do this using python-chess ... but a tried and tested tool would be preferred)

Cutechess is a very good solution for this. You can use either the CLI or the GUI to run matches of engines (both UCI and XBoard protocol), and at least the CLI even supports SPRT as a termination criterion of the match, see the help.

Cutechess is also heavily used in the development of Stockfish when running matches between different versions of Stockfish on fishtest.


How do I to convert tarrasch-base.tdb into pgn for scid? I have a tarrasch database in a tdb file that I would like to run into my scid-vs-pc gui. But after spending a lot of time looking for some information on Google, I found nothing that can help me. How do I to convert tarrasch-base.tdb into pgn for scid?

The Tarrasch Chess GUI is an open source, free Windows download. It uses a proprietary database format and the author approached Mark Crowther, the brains behind TWIC to ask if he could use Mark's database of games. Mark agreed but part of the way Mark makes his living is by selling his full database. There is an export to pgn format function in TCG but to protect Mark's work this feature is limited to 10,000 games.
So, provided your tdb consists of fewer than 10,000 games you can download the program, import the tdb database and then export as pgn. If, on the other hand, you are trying to rip off Mark Crowther's database you are SOL (out of luck). If you are determined to deprive Mark Crowther of his dues for developing his database then your best bet is to download the TCG source code, extract the code for pgn extraction and modify it.


Playing the French Defense Exchange Variation In the French Defense Advance Variation, 1. e4 e6 2. d4 d5 3. e5 ..., there are some clear game plans for both sides, areas where you want a pawn break, where you want to attack, etc.

However, in the French Defense Exchange Variation, 1. e4 e6 2. d4 d5 3. exd5 exd5, things are different. What are white and black's goals? Are there any key concepts or underlying strategies? After developing my pieces, and playing logical attacking and defensive moves, I start to wonder "what I am trying to do?" and I usually don't have a good answer to this question. It feels very strange to play this, and I am looking for some tips and ideas about playing the exchange variation as white.

First, a side note: I play the black side of the French Defense almost religiously, and my results against the Exchange variation have traditionally been very good. It's not a variation that's feared by most French Defense practitioners. Neither, for that matter, is the Advance variation, which gives black a very clear plan of strategic counterattack based on undermining the white center, freeing the poor light-square bishop, and sometimes pressuring the white queen-side pawns. There are also lesser-known closed lines of the Advance involving a ...c4 pawn push that, while objectively tend to lead to equality, are very promising for the black player who is more familiar with their nuances than his opponent. If you really want to give French players trouble, consider learning to play (one of) the Tarrasch, Steinitz, or Classical variations.

Anyway, back to your main question. Normally, it's asymmetry of position that informs/determines the respective strategies that both sides attempt to realize. The exchange variation, however, is inherently symmetrical and therefore no clear, overarching strategies present themselves until the symmetry is broken by either white or black. There are a few proactive ways of creating asymmetry in this variation:

4. c4 which usually leads to IQP positions with all the attendant and characteristic advantages and disadvantages. The player with the IQP is advised to play aggressive, attacking chess and avoid liquidation of material (unless doing so yields an obvious benefit), as the IQP could be easily blockaded and made into a major weakness in the endgame.
Preparing queen-side castling and launching a pawn storm if black chooses to castle king-side. This is highly double-edged and possibly questionable in its soundness, but a viable choice if you enjoy very sharp games and are confident in your tactical abilities.

Other moves are mostly noncommittal and give black time to develop as he chooses. Ultimately, if neither side breaks symmetry in any substantial way, the game is probably going to revolve largely around control/occupation of the squares e4 and e5. Further, numerous minor piece trades are very likely to take place on the e-file in such situations, leading to drawish positions.

One general piece of advice I'd offer, if you insist on playing the Exchange variation at all, is to delay it by one move and play 3. Nc3 first. In that case, if black opts for the Winawer variation with 3... Bb4, there's an argument to be made that, after 4. exd5 exd5 5. a3, black simply doesn't have any great choices (i.e., he must either effectively waste a move retreating the bishop, or cede the bishop pair, when the doubling of white's c-pawns could even be viewed as an asset in many situations because of their superior centralization). On the other hand, if black plays classically with 3... Nf6, he has lost the possibility of playing the pawn to f6 (often a good choice in many lines of the exchange variation because it helps to control the key e5 square and restrains white's minor pieces).