Who did Nigel Short really play on the ICC in 2001 when he thought he was playing Fischer? In 2001, Nigel Short went public with the opinion that he had in fact played Bobby Fischer on the Internet Chess Club.
This was denied by Fischer himself, and the consensus seems to be that it was not in fact Fischer that he was playing. However, though I have the impression of reading something about who Short was really playing some time ago, I cannot remember this for sure and now cannot find a conclusive source on who Short's opponent actually was. Has there ever been a definitive statement on this?

Nobody knows who he played, because nobody has come forward to take credit; however, some chess sleuths compared the moves against various engines and found that there was considerable evidence to support a particular engine (I believe it was called "blitz tiger") as the mysterious Fischer.  Because of the incident where Short chatted with Fischer, there must have been a human behind the account as well (many accounts on the ICC are run entirely by computers without any human interaction at all).  The ICC can probably do some user profiling to figure out who the player is either by comparing the location/IP/e-mail to another user or by doing some internet forensics based on information they gathered from the incident.  However, it seems like they either don't care or if they did find out, they don't want to share (based on what xaisoft said) so it will probably always be a mystery.  And, to be honest, it's a better story that way, and because all this is is a good story, that's a good thing.

What you all fail to understand is that no computer in the world in 2000 and 2001  would castle its king and queen, double castle, or make 10 bad unorthodox moves in a row.  So this was a person. A fact that I know is that there is more than one guest71, and the ICC knows this.


Why is the light-squared bishop considered White's best bishop? The same question applies to Black where the dark-squared bishop is considered Black's best bishop.

This was from the book "Logical Chess Move by Move" by Irving Chernev where he quotes Siegbert Tarrasch as saying the King's Bishop is the greatest attacking piece, so I guess it does pertain to mainly one player with one school of thought.  I found it interesting how Tarrasch at times would not even move his King's Bishop during a whole game.

The black king, will occupy e8 and g8 (before and after castling, respectively), both of which are white squares.  Also, the weakest point on the black kingside is f7, again a white square.  Because of this, if you are trying to attack the king, the white bishop can often be more valuable.

Perhaps someone else can add some more deeper reasons, but this has been my experience.

Added: Also worth noting, attacks on h7 can often threaten mate, another white square.  Furthermore, just having the bishop on the diagonal attacking f7 would pin the pawn to a castled king.

The White bishop is whites best piece after the queen as it’s the active bishop, and can also fianchetto the king side.  In which case can be worth up to 4.5points.  Also, Fischer has elected to capture a bishop rather than a rook, such is its strength esp at defending the king.  Likewise with the black side, the white bishop is often referred to as the problem bishop often getting blocked in or not being developed to a good square.  A lot depends a lot of a lot of things, I'm a very open player, and I protect my white bishop, its worth more than a knight, bishops are like my children and the white one my favourite. ;-)  watch some of Fischer's games, he is the main exponent of the white bishop and has even traded his queen for the opponents bishop!


Which chess website with the most correct online rating? I recently switched from chess.com to
lichess.org. This was because I enjoy live chess more and it seems like can find more live chess on Lichess while it chess.com keeps you waiting. Chess.com searches for who they think is your perfect opponent whereas Lichess lets you play whoever you want.
However, I’ve noticed that Lichess gives more points to the winner and takes away more points from the losers, and I mean much more. I don't know if I'm correct though, but I think I am. Lichess also gives youn a higher starting rating.
If I'm right, then which online chess website gives the most realistic chess rating to its users?

How do you define realistic for chess ratings? Actually, they are all realistic. Ratings should be considered inside their own population because your rating in server X is your performance relative to other players in the same server. As it depends the population you shouldn't compare one rating to another rating in another server. But if you really want to compare your rating to another population approximately, please see this method: How does Chesscube.com rating compare to USCF and FIDE ratings?

All chess rating systems follow almost same rules, but they have different converging speeds. This is what you explained in your question, one server gives less on win and takes less on loss, another one gives/takes more etc.

There is a thing, K-factor, in USCF rating system for example, to tweak this converging speed from game to game. Please see this topic: What does "half-K" mean in the USCF tournament rating system?

When you enter a rating population as a new player, you start with average rating of that population(generally). But it doesn't matter which rating you start with, even if you start from 3000, you will converge to your real rating as you play games. So, it's not about being realistic again.

And generally for all rating systems, your first 8 to 20 games will have super high converging speeds, to approximate your rating faster. After that, converging speeds drops to normal and ratings get stabilized.

So, shortly, your ratings will be different in different populations, and it's totally normal.

Opinion and subjective.
There is no way to tell unless you provide a very detailed description of how you would evaluate each site.
And no rating system is that accurate even if all the players were consistent and no beginners were improving to further disrupt things.
Even if it could be accurate no system would have enough games from enough people to be accurate except in small groups that have many common opponents.  That is why when a hotshot from moosejaw or podunk goes to the big city to play in a tournament they get creamed by lower rated players because theirs had inadequate range of competition to be valid.


What should I study? My ELO is 2050. I had not played chess for 4 years until I moved to Amsterdam. In Amsterdam I joined a chess club which has many strong players. Every Tuesday we play 90min + 15sec incremental games each other.(I played 6 games)

I noticed that I could not calculate well enough for the last 3 games which I lost. Also I do not have solid opening knowledge. I started to study tactics from chesstempo. Am I on the right track?

Whenever I haven't played for a while I go through a book with 200 mate in two exercises. Easy stuff, but quite a lot, just to get into gear again. Chesstempo will serve a similar function for you.

But that is just to shake off the rust and not blunder too much. To get back to the playing strength from four years ago or to become even stronger, you should rather train calculation instead of tactics. I.e. not just combinatorial vision but the systematic calculation of long lines. The Dvoretzky books have exercises for that, but those are pretty difficult.

The main point is that in my experience servers on which you solve timed problems aren't really suited to improve calculation. Even just picking random positions from these 10000 puzzles and calculating them like you would in a game is a better way.

You should also reacquaint yourself with your openings, by looking up your old repertoire lines and then play some internet blitz to get a feel for the variations again.

You are in the enviable position of living in Amsterdam so you don't really have to spend money on books yet. The Max Euwe Centrum has a library of chess books in many languages, entry is free and you'll find the newest books on every possible opening and avenue of chess improvement.

I would recommend the book by Polgar "5334 Problems, Combinations and Games." It is good way to get into the habit of calculation.

I recommend studying openings with a computer. This will help you identify why many moves are bad, something opening books don't tell you. It is a lot more important to know why a move in the opening is bad, than why a move is good.

For players of all levels, including masters, it is often a good idea to study the endgame because usually that part of their skill is the weakest, so you stand to get the most by studying it. In other words, it is low-hanging fruit.

I would recommend Nunn's books, especially "Secrets of Rook Endings".

Also, "Secrets of Pawn Endings" by Karsten Muller.

Learn just those two books solid and you will be amazed how you can beat the crap out of anybody in an endgame.

One final comment about the endgame: often in modern swisses with short time limits you have to play the endgame really fast, somethings blitz sudden death. In those situations the guy who knows the endgame ahead of time will CRUSH the other guy. Even with time on the clock it can be really hard to find the right move in an endgame. You have to know it ahead of time. In a blitz situation, people will play just incredibly bad moves one after the other in an endgame.


Easy variation to learn with White against Semislav with not many lines and avoiding the Slav at the same time if possible I'm looking for an easy variation to learn against the Semislav. Note that I play d4, c4, Nc3 against many openings. I tried to play the 5.Bg5 line but I felt that it was full of memorization:
[FEN ""]
1.d4 d5 2.c4 c6 3.Nc3 Nf6 4.Nf3 e6 5.Bg5

So I switched to playing the Bogolyubov line which avoids the Slav dxc4 because my Bishop can take it with temp:
[FEN ""]
1.d4 d5 2.c4 c6 3.e3 Nf6 (3...Bf5 4.Nf3 e6 5.Be2 Nf6 6.O-O) (3...e6 4.Nc3 Bb4 (4...f5)) 4.Nc3 e6 (4...g6)(4...Nbd7)(4...a6)(4...Bf5) 5.Nf3 Be7 (5...Nbd7)(5...Bd6)(5...dxc4) 6. Bd3 Nbd7 (6...O-O) (6...dxc4) 7. O-O O-O

Btw, I tried playing the slav with white before switching to the Bogolyubov line as
[FEN ""]
1.d4 d5 2.c4 c6 3.Nc3 Nf6 4.Nf3 dxc4 5.a4

But I didn't like them that much. Maybe because I haven't read about them a lot. As you can see, there are tons of variations in the Bogolyubov line, including the Meran. It's too much! I would really appreciate it if somebody can give me either an easy line against the Semislav that avoids the Slav, or two easy lines against Semislav and slav.

The easiest to learn is the exchange variation.  It leads to the persistent opening advantage, but doesn't offer much opportunity for a crushing win.  This is the line I played when I had to face the Slav.

[FEN ""]

[White "?"]
[Black "?"]

1. d4 d5 2. c4 c6 3. cxd5 cxd5 4. Nc3 Nc6 5. Nf3 Nf6 6. Bf4 Bf5 (6... a6 7. Ne5)
7. e3 e6 8. Bb5 Rc8 9. Qa4 Nd7 10. Bxc6 Rxc6 11. Qxa7 Qc8 12. Qa5 Ra6 13. Qc7
Qa8 14. O-O Bd3 (14... Rc6 15. Nb5) 15. Rfc1 Rc6 16. Nxd5 exd5 17. Rxc6 bxc6 18.
Ne5 Nxe5 19. Qxe5+ Be7 (19... Kd7 20. Qc7+ Ke8 21. Rc1) *

1PK4  aka  e4  would avoid the slav  issues.
My experience says there is no real answer to what you wish were possible after you start with  1 d4 d5 and 2c4 c6 then  3 nc3.


Two knights can move to e7, but the move is only specified as Ne7 In the diagram below, Black makes the move denoted as “Ne7” which moves the black knight on g8 move to e7.
[StartFlipped "0"]
[FEN "r1bqkbnr/pp3ppp/2n1p3/1BPpP3/8/4B3/PPP2PPP/RN1QK1NR b KQkq - 0 1"]

1... Ne7

The problem is, based on my limited knowledge about chess, “Ne7” should be ambiguous in this case since also the black knight on c6 can also move to e7.
How come we need only to write this move as “Ne7”? Is it simply a wrongfully written move?
I found this PGN online, so I have not written/played them myself. I would rather not go in and correct the moves myself, and I would rather find a way to disambiguate them correctly.

The c6 knight is pinned by the bishop on b5. Note that if the c6 knight were to move it would leave Black's king in check, which renders any such move illegal.

Therefore it is ok in this case to write "Ne7" instead of "Nge7", since the pin means that there is no ambiguity as to which knight moves.

This is an error.

When two pieces of the same type can move to the target square, you must specify enough information to make the move unambiguous.
The person / computer notating this should have switched to algebraic notation (g8e7) or specified Nge7.
If a human entered this, then it was human error, plus a system that doesn't check for such errors.
If a computer entered this, it's a bug.


How do I analyze my game after playing? What techniques do you use to analyze your games or other people's games?

How much time do you spend on analyzing the game?

Are there any tools (electronic or manual, such as a piece of paper) you use during analysis?

Analyzing your own games is the best and fastest way to improve in my opinion.

As soon as possible after the game, write down the variations that you were thinking about during the game, especially the ones that were not played.  This will be useful when you come back to the game after days, months, or even years.  As you improve, it will be helpful to see what you were thinking during the game.  That way, you can pinpoint how you can improve your thought process in future games.

When you start analyzing, use a chess board, but don't use an engine at first.  Look for moves where you made a mistake or missed something important.  If you lost material, go back and find the moment where you blundered.  If you got into a bad position, try to identify the moves that led to that position and evaluate some alternatives.  Put everything you come up with into your chess program/database (you are using some kind of a database, right?).

After you've gone over the game "by hand" (this should take at least half an hour for a slow game, even more time if it was a complicated position), now it's time to use a chess engine.  Go through all of the moves and take note of where the engine says that you either made a poor move or missed an opportunity for a better move.  Again, add variations to your database.  If it's not clear why something that the engine suggests is good, investigate it further.  Try out some lines and see what the engine says.

At this point, you have an awful lot of moves in front of you.  Now it's time to try to take away some lessons from the game.  Go back through the game again and decide what specific thing you could have done better.  Did you make a very poor positional move?  Did you blunder material?  Did you neglect development?  Did you put a piece on a bad square?  Asking questions like this will help you in future games during the game.

The last thing that you can do is to ask a stronger player for help.  Bring all of the information you have to the stronger player and then go through the game once more.  The stronger player can give you suggestions for how to think in certain positions.  Basically, a chess engine can tell you what the right move is, but a stronger player is often needed to tell you why a move is correct.

You should try to develop your own analysis style as well.  If you are a strong tactical player, try to go through the game without making moves on the board, just analyze in your head.  If you are good at endgames, switch colors and analyze where your opponent went astray in the endgame.  Hopefully analyzing games is fun and not a chore!

Additional thoughts

I didn't mention studying the opening moves because that is less important than finding the specific points in the game where you made a mistake.  After you have looked at the game as a whole, studying the opening can often help you as well.  The best way to do this is to look for grandmaster games in the same opening that was played.  Find out what moves are commonly played, and then go through some games of stronger players in order to find good, general plans for the opening.  Try to see where you varied from these plans and determine why you didn't do what the stronger player did.  This is much more important than memorizing moves (although you will probably find that you've memorized many variations just as a matter of course!).

This platform Chess.com has what you are looking for. Each games can be reviewed at your own pace with/without comments. So sign up for free, play a bit and run the post game analysis.

https://www.chess.com


Bird's opening problems I've played the reversed Leningrad Dutch for some time, and I have the problem that when I play Nd2, Black forks my rook and queen on f6->g4->e3. I never get to push my e-pawn before Black forks me in some cases. Is there any solution to this problem?
Here is a sample line.
[FEN ""]

1. f4 d5 2. Nf3 c5 3. g3 Nf6 4. Bg2 Nc6 5. O-O e6 6. d3 Bd6 7. Nbd2 Ng4 ( I have wasted a move on Nd2.)

You have some options.  You could abandon 7. Nbd2 because it allows 7. ... Ng4; the standard choices in the main line are 7. Qe1, 7. c3, and 7. Nc3, much like the regular Leningrad Dutch.  If Black plays Ng4 while you still have e3 covered by the Bc1, you can simply proceed with your plan to push e2-e4, and maybe later kick the knight with h2-h3 to get an attack going on the kingside.  Just make sure to keep an eye out for tactics on the a7-g1 diagonal as long as Black has a knight on g4; Bird's Opening can get ugly for White fast if you miss seeing a tactic.  You'll still need to pay attention to e3; Black's main try in the strongest lines is to play d5-d4, possibly following up with Nd5, and eventually you'll need to be prepared to play against that.  If your opponents are still gifting you e6 setups though, that might be a ways off.
In the specific position you've shown with Black's lackluster e6 setup, you have the option of going straight for 7. e4 as @bof and @pulsar512b discussed, but that idea won't ordinarily be available if Black plays more demanding lines.
If you're dead set on making 7. Nbd2 work instead, then 7. ... Ng4 8. Nb3 doesn't look like the absolute end of the world to me, but the positions aren't pleasant and Black is calling the shots.

Yes. Do not play Nd2.
It is better to not play that variation of the reversed Dutch.
It is best to just play 1. e4 and avoid the issues with Birds.


How do Kramnik and Topalov indicate a resignation when they play together? From What is the correct resignation procedure? it is clear that, although FIDE has no special rules governing on how you resign, it is common to either offer your hand or make some sort of exclamation (i.e. "I resign!"). What is important is that your intention to resign is unambiguous.

Now, the rivalry between Kramnik and Topalov has gone to such an extend that each player refuses to shake the other's hand or engage in any kind of pleasantries. Which raises the question - how do they go about resigning when playing each other without creating confusion about their intention?

If I remember correctly, they either just sign the scoresheet or stop the clock first and then sign the scoresheet to indicate that they resigned. There is no handshake, and they do not speak to each other since the WCC2006 controversy.

Here are two examples:
Candidates Tournament 2014, Rd. 13 (Kramnik-Topalov 1-0),
Norway Chess 2014, Rd. 6 (Topalov-Kramnik 1-0).

Addendum. Not asked in the original post, but one interesting (and related) question is also: How do Kramnik and Topalov agree to a draw? Signing the scoresheet or stopping the clock is not appropriate in this case, since the opponent might want to continue playing.

One obvious way is to repeat the position three times. If there is no threefold repetition on the horizon, the players can offer a draw through the arbiter (like in Sofia rules, used, for example, during the WCC 2010).

Knocking over your king has always been a perfectly acceptable way of resigning.

With the king being the tallest piece on the board it can often happen that somebody wearing a long sleeved shirt can accidentally knock over their king when moving a piece near the king. I often, as a joke, hold out my hand before they've had a chance to pick the king up as if accepting their resignation. If they look puzzled rather than amused I point to their horizontal king. Hopefully at that stage they'll smile.


In engines vs engine game, both think "optimistically": that they are in better shape than what their opponent thinks the evaluation score is I observed in many Tcec games of season 10 (and possibly repeats trough seasons) that white evaluation score of a position is always greater (not in terms of absolute value, but in terms of the ">" math relation) than what their oponent thinks.

Now, the engines don't both evaluate the same position, they evaluate only their own moves, so to compare, I'm comparing with the previous and following move, in average.

You can see for yourself that in the Tcec link at the beginning, down there is the "Evaluation" graph. And the white "curve" is over the black in most game most of the time.

What causes this phenomena?

Is that after making a move the position is improved for our side and the evaluation changes accordingly?

I don't think, evaluation shouldn't depend so much on side to move. Is that a engine always do the things he likes, which the opponent maybe likes but maybe not and thus differing in the evaluation?

It doesn't really matter what the absolute scores are, they really only serve to compare moves internally so only their relative values matter.

With one exception: positions that are evaluated at a draw get 0.0 by all these engines.

So this "optimism" factor is tuned to create a difference between a position that is merely equal and one that is a draw; if it's set to +0.1 for an equal position, then a position must be worse than -0.1 before taking a draw becomes preferable.

The usual name for this is the "contempt" setting. The current TCEC Rules say that the engine's default setting is used, so it can be set by the programmers before the tournament, and updated versions of the program can be entered for later stages of the tournament.

I think that in stage 1, an engine that has too many draws won't qualify for stage 2, so I'd expect some slightly higher than normal contempt, and this effect should be clearly lower in later rounds. But I'm a complete layman and this may be wrong.

That is simply not true.
In a lot of positions, black is 'more optimistic' than white.
Those are just 2 separate evaluating entities with their particular evaluation terms and understanding of the position.
I guess you simply happened to browse games, where white was more optimistic.


Programming three-fold repetition for my chess engine I'm making a chess engine that has to implement a three-fold repetition as my AI vs AI engine repeats the same moves over and over again (Have a look at my post here - My chess AI makes the same repeated moves). I've read the rules of this scenario from the wiki and would like to implement it. I'm not sure if I have understood the rules thoroughly, so what I'm doing here is -

Checking if the present move made (from the movelog I have) has already occurred before.
If it did, check for one more occurrence (as we need three in total).
If the moves pattern for all the three re-occurred moves is same, return true.

Please have a look at my Java code and suggest me the corrections.

    boolean isThreeFoldRepetition() {
        List<Move> allMoves = Table.get().getMoveLog().getMoves();
        int currentMoveIndex = allMoves.size()-1;
        int secondFoldMoveIndex = currentMoveIndex - 4;
        int firstFoldMoveIndex = secondFoldMoveIndex - 4;
        int distance = currentMoveIndex - secondFoldMoveIndex - 1;

        while(firstFoldMoveIndex >= 0){
            Move thirdFoldMoveMade = allMoves.get(currentMoveIndex);
            Move secondFoldMoveMade = allMoves.get(secondFoldMoveIndex);
            Move firstFoldMoveMade = allMoves.get(firstFoldMoveIndex);

            if(thirdFoldMoveMade.equals(secondFoldMoveMade) &&
               secondFoldMoveMade.equals(firstFoldMoveMade) &&
               firstFoldMoveIndex - distance >= 0){
                int gap;
                for(gap = 1; gap <= distance; gap++){
                    thirdFoldMoveMade = allMoves.get(currentMoveIndex - gap);
                    secondFoldMoveMade = allMoves.get(secondFoldMoveIndex - gap);
                    firstFoldMoveMade = allMoves.get(firstFoldMoveIndex - gap);

                    if(!thirdFoldMoveMade.equals(secondFoldMoveMade) || !secondFoldMoveMade.equals(firstFoldMoveMade))
                        break;
                }
                if(gap == distance)
                    return true;
            }

            secondFoldMoveIndex -= 2;
            firstFoldMoveIndex = secondFoldMoveIndex - distance - 3;
        }
        return false;
    }

Threefold-repetition is about a position (not moves) occurring three times. Those positions do not have to be reached by the same moves.

Also (as this also seems to be confused sometimes) it is completely irrelevant when this happens, e.g. you can have the same positions after moves 10, 42 and 63 and it would still be a draw.

You should check whether the position is repeated. So basically at every move you need to check whether the position occurred in the game before. By position I mean the same position of all pieces on the board and the same castling rights and the same player to move and the same enpassant rights. That is, basically you are checking whether the FEN are the same (except for halfmove clock and fullmove number).

Something like:

int positionCount=0;
while(iterate through game positions) {
    if ( positionToCheck.piecesPosition == iterationPosition.piecesPosition &&
         positionToCheck.castleRights == iterationPosition.castleRights &&
         positionToCheck.enPassantRights == iterationPosition.enPassantRights &&
         positionToCheck.playerToMove == iterationPosition.playerToMove ) {
      positionCount++;
    }
    if (positionCount==3) { return true; }
}
return false;

Of course you can simplify the above algorithm. E.g. you only need to iterate over position with the same player to move. Also you only need to iterate over positions back to the last pawn move, capture or castling move.

Why not just keep a map indexed by the position hash pointing to a count of how many times it has been seen so far?  No iteration required... just update the hash as you traverse the move tree.


Why does White play g5? As a total newbie, I've been solving some medium-level problems on chesstempo. This one caught my eye. We play as Black after White's first move.
[FEN "6k1/5p1p/5bp1/p7/P1r3PP/2n2N2/4NP2/1R4K1 w - - 0 1"]

1. Rb8+ Kg7 2. g5

What I can't understand is why White plays g5.
It is a quite poor attack on the bishop as Black then plays Ne2, capturing the White knight and checking the king. Therefore White loses the knight and does not get to capture the bishop. Instead, White could have at least exchanged the knights:
[FEN "1K/2PN/2N2n/PP3r1P/7p/1pb/pkp/6R w - - 0 1"]

1. Nf6 Rf6

I this reckon to be a fine attack on h4 pawn as the White knight (which is protecting it) should be moved not to be captured by the rook. Yet, from White's viewpoint, I believe having the knights exchanged and the pawn captured is better than having the knight captured and leaving Black with all the pieces.
What is the point of such a move? What am I not seeing? Why are the moves I made (Nf6, Rf6) not right?

Black doesn't actually win a piece.
After 1.Rb8 Kg7 2.g5!? Nxe2, White will parry the check by playing 3.Kf1, when both the Bf6 and the Ne2 are under attack. You cannot save both pieces with 3...Nd4 attacking f3 and hoping for 4.Nxd4? Bxd4 because 4.gf6 is check.
As a consequence, Black wins a pawn and retains a winning position, but they don't pocket a piece.
Alternatives on the second move to 2.g5 are hardly better for White because their Pg4 is hanging with check, e.g. 2.Nxc3 Rxg4! (and not 2...Rxc3) 3.Kf1 Bxc3 with, once again, an extra pawn and a winning position.

White is a patzer.  Or this was a very fast speed game or he was in severe time trouble.  Or the position is wrong.
After white g5,  black plays nxr and white plays pxb losing the exchange.
white has no way to mate with the horsies and black wins easily.


How can I tell when to sacrifice? What are factors to consider when and when not to sacrifice? For example, imagine in a game where your opponent puts his bishop in direct sight of yours and you're not sure whether to take it or not? Is it safe to assume that one of the factors would be if your bishop is bad, then it might be a good idea to sacrifice it especially if the opponent has a good bishop?

Sacrifices have the following goals:

exposing the king: for example after your opponent castled, sacrificing the bishop to take the pawn diagonally to the king.
cut the escape of the king: this one is hard to explain, but basically after the sacrifice, if the opponent recaptures, the king can no longer occupy this square. Note that this can also happen even if there was an enemy piece originally, and you sacrificed by capturing it, but under the scenario that the new piece there have different mobility (e.g usually a knight) so after a check this new piece can't block it as opposed to the old piece.
gaining (or making the opponent lose) tempos: sometimes you find combinations that allows you to make important moves in time, or make the opponent lose time that he doesn't have. One example is if the two players are about to promote, but you sacrifice a piece so that the king blocks his own pawn or moves into a square that will be attacked by the promoted Queen (so when you promote you deliver a check).
gain control of the center (or any other particular area): this usually happens by sacrificing pawns from the flanks to be recaptured with enemy pawns from the center.
weaken the pawn structure: in very closed positions, these kind of sacrifices are almost always played. I can't give examples since I have never done one and usually don't understand them without computer analysis.
removing of the defender (deflecting): when a piece is the only one stopping the inevitably, it is usually worth taking it down no matter if you lose material.
luring a piece to unwanted squares: luring the king into forks, screws, etc. Another example is when a enemy bishop is preventing your pawns to advance, making him move out of that diagonal is deadly.

Some quick examples from one of my games:

[FEN ""]
1. e4  e5 2. Bc4  d6 3. Nf3  h6 4. O-O  Nf6 5. Nc3  Be7 6. d4  exd4 7. Qxd4  O-O 8. Be3  Nc6 9. Qd3  Bg4 10. Bxh6  gxh6 11. e5  Nxe5 12. Nxe5  dxe5 13. Qg6+  Kh8 14. Qxh6+  Kg8 15. Ne4  Be6 16. Rfe1  Bxc4 17. Nxf6+  Bxf6 18. Re3  Bg5 19. Rg3  f6 20. Qg6+  Kh8 21. Rh3+ 1-0

(#1) - 10.Bxh6 might not be the best move from that position, but it is not a bad one either, there is a very dangerous pin by the white bishop that together with the Queen can do amazing things. The main idea is to expose the enemy king.

(#3 and #6) - 11.e5 if the Knight moved, I would have achieved #6 over the bishop, however he didn't and decided to take the pawn, I didn't care which way he take the pawn, my #3 is achieved since all I wanted to free the Queen diagonal.

(#6) - 15.Ne4 I attempted to remove the defender of the bishop, with the plan of capturing the bishop with this line 15.Ne4 Nxe4 16.Qg6+

(#3) - 16.Rfe1 is also interesting, some people would say it is not a direct sacrifice though, but it is deliberately not protecting a piece. The main idea is to don't waste any time and activate the rook ASAP, while still having a chance to protect the other piece if he decides to go for NxN first.

Measurable gain is not a sacrifice.

There is a percentage of physical and before so don't hesitate, which capacity is been already accumulate for gain....


Rook ending with single distant passed pawn 6k1/1R5p/6p1/p7/8/7P/r5P1/6K1 w - a6 0 33

Is it possible for White to hold a draw in this position? If so, what is the strategy?

Typically I lose these ones and draw when it's me with the extra pawn...

This should be a draw as far as I know and the first step is to get behind the pawn with your rook. Now if black pushes the pawn to the second rank it is an easy draw, because he can never move the rook without you taking the a-pawn and if he tries to protect the a-pawn with the king you will just give checks from behind.

8/R6p/6p1/8/8/1k5P/p5PK/r52 w - a6 0 33

In this position you just check with Rb8+ and go on checking until his king leaves the a-pawn. Then you go straight back to attacking the a-pawn otherwise Rh1+ wins for black.

So what he might try is pushing the pawn only to a3. Then he has a place on a2, to hide his kings from the checks. But now the problem for black is that he doesn't threaten to move his rook away and queen the pawn, therefore your rook isn't shackled to the a-pawn. That means as soon as his king leaves the kingside pawns, you just snatch them off with your rook.

8/8/R5p1/5k1p/7P/p5K1/6P1/r52 w - a6 0 33

Something like …Ke4 Rxg6 Kd4 Rg5 Kc3 Rxh5 Kb2 Ra5 ...

Given that his king has to run all the way to the a-line, then move the rook and make two pawn moves to queen the pawn, this should give you enough time to push your own kingside pawns. When you finally have to give your rook for the a-pawn, ideally your kingside pawns (supported by your king) are so far advanced that his rook cannot deal with them.

I would recommend reading Nunn's "Secrets of Rook and Pawn Endgames."

There is no simple answer to your question, because some positions are draws, others are wins. Also, skill makes a huge difference. A player who knows the right techniques will always outplay someone else in this kind of position.

For example, BlindKungFuMaster is pretty typical in making a lot of incorrect assumptions. Even though I am the same strength as him, I bet I would easily beat him as Black in this position even though we have the same rating. First of all, Black will not move his pawn and box in his rook as shown in that answer, but will fight with his rook in front of the pawn.

There are a lot of subtleties in these positions.

Your best move: study Nunn's book cover to cover.


Computers finding computer moves There are positions in chess where the only good move (e.g. only move that preserves equality) is very unnatural for a human player. For instance if this move goes against common principles or if it opens the king to a potential attack, a human might be less likely to play this move.

Have there been attempts to find such positions with a computer?

I am not interested in using this to identify cheaters (=humans using illegally computer help in chess).

I am more interested in whether this could be used to win equal positions against humans. For example with such analysis, one could improve opening preparation, steering towards positions where the opponent has to find a "computer move". Also in endgame studies it could be used for the same reason.

One of the most common "unnatural" moves for a human is an under-developing move. Computers find them easily, as it's just another move to check but human's have invested time and energy developing a piece - why then move it back again?

Computers just crunch and then evaluate. Humans are much more emotive and have certain biases for development so it's very easy as a human to overlook a move that a computer would find in a heartbeat.

(one example might be re-routing a queen from one side of the board to the other, via the home-square - e.g. Qa5-d8-h4)

I realise this is a general answer but might help :)

First off, this is a very valid question.

The short answer is that no - to my knowledge, there are no programs that can somehow "steer" the game into positions where "unnatural" moves are good. While it is certainly possible to create such an engine, remember that a natural move is subjective.

However, you don't need a computer program to do it for you! You can do it yourself. Select a complicated opening, especially something like the Najdorf or some other sharp line, and you'll notice that there will be many opportunities for you to lead your opponent into muddy water - complex positions where you know the theory sue to computer analysis, and your opponent might not.

Here's the thing though; to attempt such a thing, you'd need to be a VERY strong player already, at least FIDE master I would say. The reason is that while grandmasters play complicated positions on purpose all the time, they have to do it to beat equally strong players. But they don't need to if they're playing against even a 2000 rated player, as they can just gradually outplay them, without need for double edged positions.

For practical purposes, I will repeat that complicated openings, which you shouldn't be playing in the first place unless you're a master level player at least, will offer an incredible array of tough positions which are amazing fro computers, yet in which humans make plenty of mistakes.

Also, note that good players will play unnatural moves if they are good! That's part being a good player - considering all possible candidate moves.

To make myself even more explicit, Kasparov once said that even he can't calculate everything. In complex positions, there naturally tend to be no real natural moves. That's where computers dominate.

(I am an expert rated USCF player)


What are the best chess blogs? I enjoy reading about chess and there is a number of blogs that I follow. And I do toy with the idea of starting a chess blog myself in a distant and uncertain future. So I want to tap your combined knowledge:

What are the best chess blogs you know?
What makes them so interesting?

(I know this is the kind of subjective question, stackexchange usually doesn't go for, but I think this could be a very worthwhile collection, possibly as community wiki.)

For players under 1800 USCF/FIDE, Dan Heisman's blog is an extremely helpful source. He has lots of information on:

Thought process: how Hope Chess can cause losses
Time Management: how to manage your time in order to be able to think as much as possible when the game gets complicated.
Practical tips for different situations: when you're way ahead, it's a different game; when you're losing, complicate the position to try to get your opponent to make a mistake; when your opponent is in time pressure, don't blitz him, etc.
Correcting misconceptions: player not recapturing because then he would get doubled pawns (safety is a 100, pawn structure is a 1), players loses because he didn't "see" something when in fact he didn't look out for it (thought process), player making a quick move in a critical position (hand-waving), Player playing a quick move because all moves look bad (acquiescing), Player rejecting move based on shallow or superficial analysis (quiescence error) . . . The list goes on, check out his blog!


Is the Sicilian Defense a good opening for beginners? Just discovered the chess section of this website. This is my first question here.
I am a beginner chess player(rated about 1300 on the chess websites) and play mainly for recreation. For a long time, my opening repertoire was restricted to 1) e4 .. e5 .

However, while playing black I get tired with the fact that white is always calling the shots, and also bored of playing the same lines. I've tried the french but find it a bit predictable for the white player and with less variety.

I would like to try the sicilian. I know that this is often preferred by grandmasters. However, the grandmasters typically gain the advantage only in the end game. However, the style of grandmaster play is quite different from the style of beginner/amateur play. Grandmasters would often go into the end game with no advantages of material. By contrast, in beginner/amateur play often the better player gains advantage in the middle game itself and by the time he reaches the end game he is already ahead in material by a rook or a bishop. Keeping in mind this difference is the sicilian a good opening for a beginner? Or is it more for the more advanced players and end game specialists?
Also, how to play it correctly? I've tried playing it a few times but am yet to understand the underlying principle. Which is the better second move -  2) .. e6 or 2) .. d6 ? Why is the rook pawn sometimes advanced prematurely ( 4) .. a6  or 3) .. a6) ? ... etc., etc.

The Sicilian is playable at all levels. 1.e4 e5 openings are easier to understand, so you will often see 1...e5 recommended for beginning and intermediate players (and I second that recommendation), but there's nothing wrong with 1...c5, and you should feel free to try it out and see if you like it.

To say how to play it correctly would take hundreds of pages. To answer your two specific questions:

After 1.e4 c5 2.Nf3, 2...e6 and 2...d6 are both perfectly good moves played at the highest levels.
The move ...a6 in the Sicilian has a few points, but the most important are that 1) it can keep a White knight away from b5, and 2) it can support ...b5 and start a queenside attack.

Sicilian will make you a tough player and will save you from early losses, as e pawn is responsible for saving the f7 pawn, and e pawn advance is delayed most often in sicilian, so there is no immediate threat from white's light colored bishop attacking f7. All openings are playable at all levels. Stick to one opening and you will slowly learn all pitfalls.


White have an advantage with the first move I am beginner in chess but in my mind one question overcome, Does white have an advantage with the first move?

It really depends on what level of chess you're looking at. At the amateur level (<2200), I would hypothesize that white's supposed "first-move advantage" is relatively insignificant. However, it's quite evident at the higher levels that white has an advantage when playing mainstream openings - please reference the Shredder Opening Database for the details of individual moves. For example, out of the 242,221 Grandmaster games where White has played 1. e4, he has scored 54.5%.

Chess players and theorists generally agree that White has a certain first-move advantage. The page on Wikipedia is certainly a fascinating read.

In high level games, white wins 30 percent and black wins 20 percent.


Are there moves in chess that are considered unsporting? In many sports, you often find legal tactics that are considered unsporting by fans, spectators and/or opponents. For example, in football (soccer), it is often considered unsporting to simply pass the ball around your back defenders instead of trying to attack. Are there any similar situations in chess?
Some examples that I can think of: perhaps it is considered unsporting, or perhaps indicative of lack of skill, to promote 5 pawns and crush your opponent instead of looking for a more elegant mate in a winning position. Also, in my school days, we used to think of scholar's mate as a bit ... unsatisfying. There even used to be a meme going around that scholar's mate is not allowed (probably started by the coach to get the kids to play "proper" chess).
To be clear, I'm not so much looking for unsporting behaviour as unsporting moves. I can imagine it being very unsporting to, for example, let your clock run out when you still have 40 minutes left rather than resigning in a lost position, forcing your opponent to hang around just in case you actually make a move.
Are there any other examples you can think of? Or is chess a case of - if it's legal, then it's good?
Update: Just as I was starting to think that unsporting moves are few and far between, Kamsky and Gareev played to a controversial draw by three-fold repetition in round 1 of the US champs. According to the GM's doing the analysis, Kamsky was pretty much forced into the draw, but Gareev had the opportunity to play an alternative move to continue with the game.
So let's say you have the following situation: player A plays against a much stronger opponent B. By luck or miracle, player A finds himself ahead in the game, and see the opportunity to force a draw (or maybe he is so far ahead that he knows player B would accept a draw if offered). Is it unsporting for him to draw the game then?

What is "unsporting"? To my mind (backed up by the two or three definitions I quickly browsed), it's mostly about behaviour. To act sportingly is to be fair and respectful, to play for the (mutual) enjoyment of the sport, and—here's the tricky part—to not abuse the rules for an unfair advantage.

Unsporting behaviour in general, and the last kind in particular, often leads to new rules being introduced. ("No underarm bowling in one-day cricket" is the first example that comes to mind.)

I can't think of anything on the board (as opposed to players' behaviour, or abusing the clock) that would strike me as unsporting. And the lack of new rules to counter anything on the board would seem to support that view.

So essentially, no: in standard chess, "if it's legal, then it's good". People might complain about how some style of play (whatever's new and trendy and effective) is changing the spirit of the game or whatever, but so far everything still seems to be fair play.

As far as I know playing for time when the game is obviously lost (i.e. trying to make it longer with generally useless moves) is considered not only unsporting but directly forbidden in some competitions.


Why is the king powerless and the queen powerful? Historically, real kings were powerful (Alexander the Great, Napoleon Bonaparte etc.) and women were powerless. The game of chess began in Asia, some say, and the women were definitely powerless there. Maybe Cleopatra was powerful, but still doesn't explain why the people who created modern chess made the king so powerless and hopeless, hiding behind his army and his queen
Is it because of Queen Mary, aka Bloody Mary Was she the one who influenced the people who created the modern chess? Is she the reason why kings are hopeless and queens are ruthless?

Practically speaking, if the king were any more powerful, checkmate or capture would be impossible.

The Queen originated as the Advisor.  The Advisor was powerful, but not as powerful as the modern Queen, however.  Why did the Advisor become the Queen?  Having more than one Queen per side would debase the game, and there are two each of the other pieces.  Thus, the Advisor is the only candidate.

Why is there a piece with huge Queen-like powers at all?  It looks like the Europeans wanted to speed the game up.  So they made a more powerful Queen, pawns started moving 2 squares on the first, and castling was created.

Finally, I am not sure that the piece we call the Queen is called that in other languages.  The game and its ancestors have piece names like camel, elephant, advisor, minister, horse, etc.

To me, it's a no-brainer. Just ask yourself, who is really in charge of the household in every culture of the world? The king is probably not at home or drunk.
If I was a king and my people would play a game with a powerful advisor I would command that the advisor should become my queen. Advisors are probably more keen on coups than the king's queen.


Why couldn't I win this Maroczy Bind (vs 2000)? [FEN ""]
[Date "6/10/2018"]
[Round "5"]
[White "Me"]
[Black "Opponent"]
[Result "1/2-1/2"]
[WhiteElo "1874"]
[BlackElo "2000"]

1. e4 c5 2. Nf3 g6 3. d4 cxd4 4. Nxd4 Bg7 5. c4 Nf6 6. Nc3 Nc6 7. Be3 O-O 8. Be2 d6 9. O-O Bd7 10. Rc1 a5 11. f4 a4 12. Bf3 a3 13. b3 Qa5 14. h3 Nxd4 15. Bxd4 e5 16. Be3 Bc6 17. Qxd6 exf4 18. b4 Qd8 19. Bxf4 Qb6+ 20. Qc5 Qxc5+ 21. bxc5 Rfd8 22. Nd5 Nd7 23. Bc7 Re8 24. Bd6 Bd4+ 25. Kh1 Ra5 26. Bg4 Nxc5 27. Bc7 Ra4 28. Bb6 Rxe4 29. Bxc5 Rxg4 30. Ne7+ Kg7 31. Nxc6 bxc6 32. hxg4 Bxc5 33. Rb1 Rxc4 34. Rb7 Rxg4 35. Rfxf7+ Kh6 36. Rxh7+ Kg5 37. Rbc7 Rc4 38. Rcd7 Rc1+ 39. Kh2 Bg1+ 40. Kh1 Be3+ 41. Kh2 Bg1+ 42. Kh1 Be3+ 1/2-1/2

My rating: 1874

Opponent's rating: 2000

I felt that I had a big initiative throughout this game and failed to convert it and ended up in a worse position in the end. Feel free to address the following points or any other analysis that is important.

I played 11.f4 with the intention of maintaining control over e5 and keeping open the option of eventually breaking with e4-e5 or f4-f5. Perhaps 11.b3 is a better first move to slow down a5-a4? Perhaps black can also consider ideas with ...Ng4.
12.Bf3 kind of feels like a wasted move at the moment but I felt it would eventually play a role in supporting a knight on d5, perhaps 12.h3 is more straightforward in this position.
I felt happy with 14.h3, considering Nd5 next.
I instantly felt that my opponent made quite an error with 15...e5.
17.Qxd6 looked safe, but perhaps I was better off with 18.Qxf4 or 19.Qxf4 rather than 19.Bxf4?!, allowing 19...Qb6+.
I didn't like 20.Kh1 Rad8 21.Qe7 Rfe8 when I have too much trouble hanging on to the b4 pawn and have to resort to Qc5, so I just played 20.Qc5 right away.
After 22.Nd5 I felt I still had a nice initiative and I really don't understand where I could've improved between now and 29...Rxg4. Maybe I could slow down and not allow 24...Bd4+? And after 26.Bg4 Nxc5 I really felt that I was losing grip.
I was a bit low on time and didn't see much better than 29.Bxc5.
In hindsight, perhaps I should've been a little more patient than 33.Rb1 and try slowly improving my position, perhaps it's still roughly equal though.
My opponent generously offered a draw after 42...Be3+ but I felt he was the one who could play on.

Also, please no computer analysis unless it's absolutely vital to explaining something. Thanks!

You couldn't win mostly due to the mistake on move 19, but you still had chances.

  I played 11.f4 with the intention of maintaining control over e5 and keeping open the option of eventually breaking with e4-e5 or
  f4-f5:

That statement is not enough of a plan, and your following moves don't support either idea.  That pawn cannot move backwards and you might wish it were on f3.

  12.Bf3, perhaps 12.h3

Again you are not playing with any plan, but Bf3 supports e4 and is probably a better square for the Bishop

  I felt happy with 14.h3

Why? How does 14.h3 help your position?  I can't help thinking there is something wrong with your position.  Your rooks aren't connected and the long dark-square diagonal is loose, but I don't know that Black can take advantage of that.

  error with 15...e5.

Yes that is dubious, and I think Black could have improved his rooks before trading knights in the center.

  17.Qxd6 looked safe, but perhaps I was better off with 18.Qxf4 or 19.Qxf4 rather than 19.Bxf4?!, allowing 19...Qb6+.

or 19.Qd8, which looks to give you a big advantage!  19...Rfxd8 20.Bxf4 Rd4?! 21.Ne2 +/-

  After 22.Nd5 I really don't understand where I could've improved

Well, what did 26.Bg4 achieve but to weaken your e-pawn?  How about, 26.Rcd1 Bxc5 27.Bc7 Ra4 28.Bg4

  33.Rb1

Why help Blacks rook get in the game?  Also, every pawn trade makes it harder to win the game.

e5! Bxe5 28. Ne7+! should do it :)

EDIT: I am wrong.


Is "Rdxd2" algebraic chess notation valid? Is the algebraic notation Rdxd2 valid?

If there is a problem with this notation, then how can it be corrected?

If you have two rooks, standing on different files (one of them on the d-file), that could capture on d2, then Rdxd2 is the correct notation.
If you have two rooks on the d-file, and both can take on d2, then use the rank number to disambiguate, for instance R1xd2.
This is according to the Algebraic System required by FIDE's Laws of Chess (see appendix C, paragraph C.10).
In the very, very rare case that you have more than two pieces of the same kind that can capture on the same square, it might be necessary to use both rank and file to disambiguate. This could theoretically be needed for queens, bishops and knights, but never for rooks. As Martin Bonner explains in the comments, for this to be necessary you would need to have a piece which is on the same rank as another of the same kind and the same file as a third of the same kind, and all three attack the same square. That is not possible with rooks.

If this notation is needed to differentiate between 2 rooks on the "d" file, then it is valid,  If there's only one rook on the "d" file, it's not invalid, but redundant.


An Interesting Idea: Pinned Pieces Stalemate I had an idea for a type of stalemate: One side is stalemated with 8 pins in a legal position with as many pieces as possible, with all of the stalemating side’s units being “necessary.”
”Necessary” is defined as either pinning a piece, blocking a piece, or covering a king’s flight square. The king must be involved of course.
The best I came up with was 22 units. What is the optimal amount?
[Title "me, chess.stackexchange.com 4/5/2019"]
[FEN "b2r2q1/1R1BkR2/8/qN1K1Nq1/8/1P1N1P2/q2r2q1/2q1q1b1 w - - 0 1"]

As a bonus optional question, what is the maximum number of units in a legal position with 4 “natural” pins, which means no promoted pinning pieces?

[FEN "b3r3/1R1p1p1q/1p1P1P1b/1Pk1BR2/1rN1K1Nq/p7/P1P1B1P1/1qn1q1nq w - - 0 1"]

Here is an (ugly) suggestion wth 29 units.

White is stalemated with 8 pins; removing any Black unit would break the stalemate. Black has promoted all of their four missing pawns (all into queens).

The three captures (white queen and 2 white pawns) ensure that this position is reachable. The three missing White pieces ensure that the position is legal and that Black could have promoted all four of their missing pawns.

The Black g-pawn captured the White h-pawn to produce doubled pawns that both promoted. The Black c-pawn captured the White queen to bypass the White pawn structure and promote. Finally, the White e-pawn was captured and then the Black e-pawn marched down and promoted.

This is optimal because 4 pawns must be promoted to create 8 pins, with requires a minimum of 3 units, thus leaving 29 left for the final position.

Regarding the bonus question, for 4 “natural” pins, here is a position with 30 units. 31 is the theoretical maximum though, since the White queen would take too many units to stalemate.
[Title "me, chess.stackexchange.com 8/9/2019"]
[FEN "4r3/1b1pB3/1nRP1pkb/pPp4p/PrB1K1pP/1P2PpP1/2R2P2/Nqn4N w - - 0 1"]


Why is there a draw in professional chess? I'm not a serious chess player, but I heard that about 80% of professional chess games end as a draw.

In other similar abstract strategy games, such as Shogi and Janggi, when it is impossible to checkmate, they evaluate pieces value and determine the winner (in a professional game).

Why does chess not adopt this way?

First of all let's put the numbers correct.

The 80% draw ratio is for correspondence chess, not something that the average person would associate with "chess".

In regular top level chess, the draw ratio is around 50%.

In either case, most games are not played out until a postions when it is impossible to checkmate, but rather most draws are agreed draws, i.e. draws in a position that could in principle be won by either player through checkmate.

If I understand your proposal correctly, you want to get rid of draws completely by evaluating dead positions (that cannot be won by either player, not even if cooperating) according to the piece value.

I see several difficulties/issues with this approach:

You'd have to decide what to do with perpetual check, stalemate and the 50 moves rule.
What do you do with positions that are equal/drawish with equal material but that are not dead draws (i.e.  either player can still checkmate)? Forcing players to continue until dead draws could lead to very long (and boring) games, similar to what we see with some games under Sofia rules.
Positions where it is impossible to checkmate are pretty rare. Basically only King vs King or King and one minor piece vs King (and a few exceptional/constructed cases). In the large majority of positions checkmate is possible if players cooperate. So the proposed change would not alter much.
If players in the dead draw position would have equal material it would still be a draw.

As far as I know, chess was invented as a metaphor to war. In war, you had the possibility of a trench warfare where neither side could make any progress, i.e. in war you could draw.

If chess adopted eliminating draws, it would lose the capability to model an interlocked battle in which no side can win.


How to exploit an opponent's time trouble? (no increment) Supposing my opponent has little time left and I have much more than him (e.g. 10 minutes to 50, or 1 to 5, or 20 seconds to 1 minute).
What are good strategies that take advantage of my rival's time situation?

I read this article, and I will quote this part which I liked:

  When the opponent is in time trouble, Webb advocated the barrage technique which involves planning two or more moves ahead, and then playing them in rapid succession. The idea is to give the opponent little time to prepare for the second move, increasing the probability of that move being a mistake. Playing a barrage of moves does increase the chance of a blunder from the barrager as well, and the technique is inadvisable in a winning position where a player should focus on winning on the board.[2]

I agree that you should focus on your own game, but taking into account the opponent's time may help you. One idea could be to delay exchanges to make the game longer and make complicated positions on the board.

Edit: I'm playing blitz/rapid chess with times between 3 and 30 minutes, without any increment, and online.

Don't try to blitz him by playing fast; now you both are playing without thinking much and you've lost the point of the time advantage.

In general, you should still just try to play the best moves. But if there is any general strategy, it is to avoid forced moves on both sides, so that he has more to consider on every move. Unless it is advantageous, don't start some sequence of captures or checks or an otherwise forced sequence, as he will be able to play a few moves in a row very fast. Keep your threats active and play quiet moves.

If he is really really low on time (like, under a minute), then while your clock is ticking he will probably be looking at a few of your possible moves and trying to come up with a response to each of them that he can play instantly. If you play a different, quiet, move instead, he is likely to waste a few seconds just trying to make sense of it before he can even formulate a good response.

I am unused to playing timed games, so excuse my poor experience.

I would suggest putting the opponent into uncomfortable situations where they must defend from several possible attacks at the same time. Instead of starting your attack, you just threaten with another piece and so on. This will (theoretically) force the opposition to increase their calculation time since they must consider so many possibilities on each move. Eventually, as they run out of time, they will begin to make desperate moves. As long as you give them as little time as possible to think during your moves, you can keep them on edge and increase the chances of making a mistake (at which point you will have multiple attacks lined up to launch in a form of barrage to gain a severe advantage). As with most approaches regarding this situation, you need to make sure you don't make any mistakes while limiting your own thinking time as much as possible. High risk, high reward.


Where can I find a whole bunch of complicated PGN files? I'm interested to test that the atom syntax highlighter for pgn files -- https://atom.io/packages/language-pgn -- can handle the full range of possible files.  Is there a suite of difficult test files somewhere?

Also related might be this question:

What are all of the possible tags for PGN?

As an author of some PGN-processing software, I would also be interested in having access to a general test suite but I am not aware of any, unfortunately, and all I can offer is some advice based on experience.

I would be wary of throwing a large database of games at an application in order to test it before you have developed reasonable confidence with its fundamentals. In the early stages, at least, I find it most effective to create a lot of small examples, each of which tests an individual feature. That way, errors are relatively easy to spot because they don't get lost in a mass of output. Once I have got rid of the basic errors I would then look at combining a small number of both related and unrelated features in individual tests to make sure that there is no unexpected interference between the associated functionality. Only late on would I switch to large datasets to make sure there are no issues with scaling up.

I also highly recommend re-running all the existing tests each time a new feature is added. I have been amazed how often I have unexpectedly broken something seemingly unrelated as the code has developed.

Apologies if these principles are already well known to you!

http://www.chessgames.com might be a good place.

Another one is http://www.top-5000.nl/pgn.htm


How good is 4. d3, the Anti-Berlin? The Berlin Defense is drawish if we reach the Berlin endgame. Yet White doesn't have to go into the endgame, and can instead play 4; d3. However, I hear that the Ruy Lopez is getting less popular in top level because of the Berlin defense. This implies that 4. d3 somehow is not as good compared to the mainlines, such as 3... a6 of the Ruy Lopez. What makes 4. d3 not as good as the Ruy Lopez's mainlines for White?

In the Ruy Lopez White usually wants to play with c3 and d4 to claim the center. If you play d3 instead then you lose a tempo if you still want to go for that plan.
Of course it is not the only possible plan but then the question becomes, if you answer 3...Nf6 with 4.d3, why would you not play the Italian instead where you might get a similar structure after for instance 3.Bc4 Bc5 4.c3 Nf6 5.d3, but arguably keep a bit more flexibility.
Still, 4.d3 against the Berlin is a fine way to play, it just doesn't have a clear benefit over other similar setups.

it depends on how good you are. At the GM level, it will likely draw a lot more than if you are not even an IM and play at a local club. 4. d3 works well for me. But then again, I am not a GM nor are my opponents.


Viewing the board from the other side I have seen a few players going to the opponent's side of the board and then observing the position from that view. They usually do it when it is the opponent's move.

Does it really help in understanding threats or traps better?

I have practiced this technique since I was 10 years old. My very first chess coach emphasized the importance of analyzing the chess position from different angles - it doesn't necessarily help me understand threats or traps, but rather assists me in understanding the game from my opponent's perspective. My opponent will be considering the position and potential plans, and it's usually easier to realize a valid plan for the other side when viewing the board from that side.

Furthermore, this behavior does tap into the psychological aspect of chess. If your opponent is unaware of this tactic, he or she may be uncomfortable that you are standing behind them as they are unused to such actions. This can play to your advantage as you can break their train of thought. Of course, you shouldn't try to distract them - it's simply an unusual act that may warrant a second glance.

Yes. This tactic works. It doesn't allow you to see traps better but what it does tend to do is unsettle the most calm and collected opponent that should be largely uncomfortable when you invade their space. I find that if you accompany this tactic with the words " ah ha" and " really and then giggle " it works to a tee.

Sincerely,

Godric


How to minimise your opponent's fun in a game? I play numerous online chess games and in this question I am self-centred: I play for two purposes:

to win the game, or when winning is unlikely, to draw the game.
to improve my chess skills, which eventually enables me to win/draw more games.

I do not care about my opponents' fun. I do not care if they feel frustrated or bored. However, I will remain polite and I am against bad sportsmanship.

Here is my logic: when my opponent finds a game non-interesting, they will more likely make inferior or aimless moves, or even blunders, and thus increase my chance of winning.

A few thoughts:

When the opponent invites me into a sharp line, decline it. Make moves to solidify my position instead. Decline most gambits.
Choose boring openings whenever possible.
Choose openings that my opponent does not like, if I know their preferences.

Is the idea of destroying your opponent's fun good? Are there any other strategies to bore my opponent so that hopefully they will lose their patience and start making inferior/aimless moves?

I play for two purposes:

  to win the game, or when winning is unlikely, to draw the game.
  to improve my chess skills, which eventually enables me to win/draw more games.

These are good goals, although you might want to add "to have fun" because if you don't have fun you are quickly going to lose motivation.

  I do not care about my opponents' fun.

Also good, because if you care too much about your opponents' fun you will end up losing focus and not follow your two stated primary goals.

  Is the idea of destroying your opponent's fun good?

No, it is counterproductive. If you start focusing on how much fun your opponent may or may not be having then this can only distract you and detract from your game. If, for the purposes of this question you are going to be truly self-centered then you cannot let your opponents' feelings, good or bad, enter into your considerations. It can only lead to bad play on your behalf. Concentrate on making the best moves.

If you are not suitably dressed, over-the-board opponents might be very distracted by your not thought out taste and poor grooming.


If elite players prefer to play short draws in knockout competitions, why not skip them and go straight to tiebreaks? From the Chessbase article covering the Jerusalem GP:

After day one of the quarter-finals finished with disappointingly short draws on all boards, FIDE Press Officer Anastasiya Karlovich made a point of asking the players about the controversial decision to choose pragmatism over combativeness. Wesley So responded impassively, pointing out that "one of us has to win" in the end. This is simply a logical consequence of using the knock-out format in events with so much at stake. Or, as Maxime Vachier-Lagrave put it:
"I understand the frustration from the point of view of the spectators, but for me it's about something else, it's about qualifying for the Candidates, so for this one I cannot be entertaining, at least not if it diminishes my chances."

Elite players are unwilling to take risks to give themselves the best chances to qualify for the Candidates, so they play short draws. Okay (I'd even say it's quite logical).
But if they're going to play short draws, why bother with actually playing out the short draw on the board? Just skip the classical games and go straight to Rapid. Or if elite players play short draws in Rapid as well, skip that too and go straight to Blitz.
Conceivably some elite players might want to fight it out in classical games, but it doesn't sound too hard to accommodate them. Ask them before the match if they prefer to draw the classical games, and if either of them say no, let the match go ahead. But if they say yes, just save everyone the disappointment (not to mention the $$$) and play Rapid/Blitz, which sounds like a much more sensible use of time. One could even use the time freed up to, e.g., play more Rapid tiebreakers, get the players to commentate, or even give public simuls.
Why haven't elite tournaments done this?

It is because there are tournament regulations, including the format, which are published before the tournament starts. You cannot really change that after a certain point, like players accepting invitations.. In addition, although certain players are amenable to draw because they believe they are better at faster time controls, by FIDE rules, they cannot technically agree to a draw before the game starts.

Also, they might sit down at the board, and play some moves to see if they actually like how the game has started, and actually press on if they like what the see.

I think that what you are asking, if they tried to do it, it might be more complex in practice, and might also have unforeseen consequences, since everyone should play be the same rules. You cannot really have some players playing it, and others opting out since everyone should play the same tournament. Nevertheless, they could change the pre-tournament regulations and try it to find out if it works.

Or why not skip blitz and use ratings or just flip a coin.

They should make them play games until somebody wins one.


How to calculate percentage of accuracy of game-play based on the number of mistakes, blunders and inaccuracies? For some time now, chess.com analysis suggests the accuracy of the gameplay based on the blunders, mistakes and inaccuracies, one committed during his/her gameplay. Now, my question is,
Whether there is any formula to calculate the accuracy of gameplay based on the inaccuracies, blunders and mistakes during the game? If not, then what are the other factors, that act on the accuracy?

The gameplay accuracy is a scale from 0 to 100 and it is calculated based on the accuracy of each of your moves. Chess.com collects a lot of data from played games that they use to evaluate which moves are more important for the final accuracy.
The final accuracy is a weighted average and that explains when you play a game with two book moves and a blunder why you can get an accuracy of 0.7 and not 66.7.
The average of a single move is determined by how close the evaluation deviates from the top engine suggestion and how far is the evaluation rank placed. If the move played was the 2nd best but was -3 instead of best -1, then that is more accurate than if the same move had 9th rank.
Chess.com has released these two articles that give some insight on the analysis:
How is it measured?
How to use game analysis?
Note:
Chess.com isn't open source and they haven't shared all the details of the calculation, so more explanation needs more speculation.

You cant.  They are just a rough guide about how you did.
The only factor is who won/lost the game.


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


How do you judge a sacrifice? I have been looking at several of Mikhail Tal's games recently, as they are exciting to analyze.  Often Tal makes sacrifices in surprising positions, and almost always the computer finds that the positions are quite close despite the massive material deficit.
How can one accurately judge the compensation from a sacrifice?  Are there any techniques to try to figure out whether or not it was worth it, and what should I be looking for here?  How can I try to evaluate "king safety" and "weaknesses," and determine whether or not they are worth the material loss?
Note: I am not just asking about a combination that returns the material.

I will assume here that you are talking about sacrificing pieces and not just pawns, which require less compensation.

For a sacrifice to work out you generally need to either 1) checkmate the opposing king, or 2) eventually gain the material back. There are other scenarios, but they're less common and I will ignore them here. Often goal 2 occurs because Black is required to give up material to avoid goal 1.

Either of those goals can be accomplished in the short term by a forced sequence that you can calculate, or in the longer term, where you don't calculate an exact sequence that will lead to your win but are confident that your good position will lead you there eventually.

Unfortunately there are not reliable quantitative compensation metrics such as "an exposed king is worth two pawns". Long-term sacrifices are generally made on intuition, which improves as one gains experience. There are some decent rules of thumb, though. Here are some good signs that your attack may succeed:

If you have two more pieces attacking his king than he has defending it.
If you are down a piece, but currently have more pieces actually participating in the game than he does (for example, both your rooks are active, but he still has one on a8 blocked in by a knight on b8).
If it is difficult for him to route his pieces back to defend his king.
If it is difficult for his king to run away (often the bottleneck is at f8).
If you have certain configurations of pieces (e.g., a knight on the sixth rank supported by a pawn, or doubled rooks on an open file) that are more valuable than you'd expect purely from their "point value".
If the king's pawn cover is broken, or if he is stuck in the middle of the board.

If, say, you can sacrifice a piece for a pawn and three of the above conditions apply, that is a good sign that the attack will succeed at one of its two general aims. But it all depends on the actual position.

My recent experience tells me that it depends on positional evaluation.  Normally you think the position would result in an attack resulting in mate or a huge material gain.
Sometimes it is forced on you.  I recall beating a much higher rated player many decades ago.   He had a positional edge and put his horsie in a strong position.  I sacrificed a rook for it plus a pawn and went on to win because I had an overwhelming positional advantage even without an attack.
That sort of thing has happened often.  Probably more than I just do it purely intentionally so as to gain some positional advantage.
But for me the common cause of winning is positional advantage from the sacrifice.  And that is hard to compute so it takes more experience and feel than calculation.


What are the differences between tactical and positional chess? Does one style of play have an advantage/disadvantage over the other?

Are today's GMs mostly tactical players or positional players?

What GMs should I follow if I want to be more of a tactical player or positional player?

I don't think one style has an advantage, or at the GM level, there would only be one style; the other would be extinct.

The very definition of a tactical player is Mikhail Tal AKA 'The Wizard of Riga.'  Others include Bobby Fischer and Garry Kasparov.  Anatoly Karpov and Tigran Petrosian are great examples of positional players.

Fischer himself said that tactics flow from a superior position.

Edit: I'd like to add that any of the top players can find the best move in a given situation. Where positional versus tactical considerations come into play is where there isn't a best move, as such.  That is, when there are several reasonable candidate moves.  Then some players show a positional tendency while others show a tactical tendency.  Petrosian, who is probably the most defensive GM, was more than able to uncork technical savagery if his opponent let him.  However, he preferred to tighten the noose instead of looking for a brilliancy.

Positional chess DOES have an advantage over tactical chess in the sense that

Having a better position will bring about checkmate where the material advantage of tactical chess

May not necessarily bring about check mate


How to deal with the Cochrane Gambit [fen ""]

 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nxf7 ?!

I'm pretty sure the Cochrane Gambit isn't correct. However, I find it difficult to defend against, as some "natural" moves don't seem to work. Can you give some advice how to deal with it? Further, I guess it might be a surprise weapon in a blitz game, so have some of you tried it out?

The Cochrane Gambit sacrifies his Knight for a few things:

He sacrifies the Knight for 2 pawns
After Kxf7, Black loses castling rights and is dangerously in the
center.
Blacks King-side is basically destroyed with only the g and h pawns
and it is not easy to find the best square for the Black King.
Usually White will check with the Bishop with Bf4 and if Black
blocks with Be3, then White should just exchange bishops and bring
the black king further into the center making it harder to castle
manually.
White wants to build a strong pawn center by pushing his pawns
especially on the king-side. For example, White wants to develop his strong pawn center by pushing d4, f4, e5 and further fortify his strength in the center with Nc3 and Bd3 or Bf4.

With the above said, I think Black's goal should be to neutralize White's strong pawn center. In the Kramnik-Topalov game, I think Kramnik made a good move with 5...c5 to challenge the d4 square. From here White has to chose between playing 6. f4 followed by 7. e5 trying to break Blacks position, but in this case White's Bishop on c1 is not playing. Topalov instead played 6. Bf4+ to not lose any tempo and 6...Be6 is basically forced and after the exchange of Bishops, Black's King is more brought deeper into the center.

Some popular replies for Black after 5. Nxf7 Kxf7 6. d4 could be:

c5
g6
c6
Qe8
Be7

Lets look at the c5 first:

[FEN ""]
1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nxf7 Kxf7 5. d4 c5

White's most popular reply is 6. dxc5, followed by 6...Qa5+ 7. Nc3 Qxc5 8. Be3 and White maintains his the initiative.

Now onto c6:

[FEN ""]
1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nxf7 Kxf7 5. d4 Be7 6. Nc3 c6

Usually with 5...Be7, Black wants to try to castle manually and White continues development with 6. Nc3. After 6...Re8, Black is in trouble after Bf4+, so instead 6...c6 with the plan of playing d5 later. After 7...d5, it might continue 8. exd5 cxd5 9. Nxd5 Nxd5 10. Qh5+ Kf8 11. Bxd5 Qe8. I would say White is better here because his Black's King is still weak and he has 3 pawns for the Knight

Regarding g6:

[FEN ""]
1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nxf7 Kxf7 5. d4 g6

g6 might be Black's most popular reply. After 6. Nc3 Kg7 7. Be2 d5 8. e5 Ne4 9. Nxe4 dxe4 10. O-O Nc6 11. Be3 h5 12. f3 exf3 13. Rxf3 Be6 14. c4. Even with this, White still has an advantage.

Last, Qe8:

[FEN ""]
1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nxf7 Kxf7 5. d4 Qe8

Here Black threatens e4. It usually continues: 6. Nc3 g6 7. Bd3 Kg7 8. O-O Nc6 9. Bd3 Nc6 10. Be3 Nb4. White may panic here because of the attack on the White-Squared Bishop, but instead of panicking, White should play 11. h3 Nxd3 12. Qxd3 Rg8. Black wants to play Kh8, so White should go for the attack with e5. Black is very disorganized and in a positional disadvantage.

In a nutshell, I believe breaking White's center as Kramnik did is the best possible way to either draw or defeat the Cochrane Gambit

I play queen to e7 and after he takes my rook, I take his pawn, check the king, and try to dominate the center with it. I dont know if it's the right way to play, but that what I would do.

[FEN ""]
1.e4 e5 2.Nf3 Nf6 3.Nxe5 d6 4.Nxf7 Qe7 5.Nxh8 Qxe4


Beginner Openings/Defenses to learn What are good openings/defenses to study for both black and white for beginners. I've messed around with the sicilian defense and it is not bad, there's just so many variations and different types of defenses/openings its overwhelming. I understand the only way to learn is to play one for a little while. Are there any sites with virtual chess boards that show step by step examples of some of the popular styles. It's not easy to learn when all you get e4, e5 nf3 etc. Are there any viable openings for white other than d4/e4, these seem overused and very cliche

In my opinion this is a pretty hard question to answer, because there is no single correct answer to it.

The choice of opening repertoire for a player should be determined by his play style, e.g. do you prefer to be aggressive always on the offense or are you more of a tactical player, looking for strategic weaknesses in your opponent's position, do you prefer closed over open positions, etc.

So my answer to your question would be to follow the basic principles of opening play:

control the center;
develop your minor pieces to their best squares;
get your king to safety;
do not move a single piece too often in the opening, unless there's a pretty good reason to do so;
do not bring your queen out too early.

From there on pick an opening that fits your play style and study the ideas behind it, not just memorize the moves, understand what each of them accomplishes.

  Are there any viable openings for white other than d4/e4, these seem
  overused and very cliche

These opening moves are most certainly not cliche. Although you might see these moves as the first move in almost every game there are lots of variations that follow. Therefore my recommendation for you would be to play an opening from the family of The Italian Game as White and maybe The French Defense as Black.

From my experience as an amateur I came to the conclusion that one shouldn't focus too much on openings. After you pick an opening that fits your style, focus on the endgame and various tactics and strategic ideas. This seems to be more efficient in the long run.

Good luck!

The d4/e4 openings are definetly not overused. They are used because they are the best openings. You should learn the stonewall attack and there is a great video on youtube about how to defend d4.


What's a good middlegame book like My System for Expert Class? I just finished reading My System. What's a good book to study afterwards for Expert Class?

I would recommend Mark Dvoretsky's book 'Strategic Play' Olms. ISBN 978-3-283-00418-7.
It's a part of famous 'School Of Chess Excellence' series. (it's easy to find it online). I personally bought all four of them:
Endgame Analysis,
Tactical Play,
Strategic Play,
Opening Developments.

Mark Dvoretsky is considered one of the best chess trainers of all time, he raised a number of leading international grandmasters.

I've read 60 Memorable Games by Fischer, Art of Attack by Vukovic, Understanding Chess: Move by Move by Nunn, and My System by Nimzowitsch.

These books got me to ~1800, but something was missing.

Before the end of 2018, in December, IM Alejandro Moreno recommended Chess Praxis.

"Another book?" I thought. Weary and withered, I reluctantly read the book. I really felt like a law student at this point (mind you, I was studying chess in a quiet area of the law library - with the rollable board and wooden pieces).

I've read Chess Praxis. Here's where it's gotten me:

(Note the highest rating in October - that was when I finished reading the three books listed at the beginning of this post, minus Nimzowitsch. I was playing sharp, but my positional play was unsound. So once I got bored of the lines, I dropped down to ~1700 (!) in a week).

And in my last USCF Tournament (2/16/19), I scored 2.5/4.0 in the open, beat an expert, drew a National Master, and took a 1900 to the cleaners. My rating exploded from 1815 -> 1880.

If there's one book you must read, it's Chess Praxis.

Reading those five books only took three months, but those will be the three most critical months of your life.


Absolute strength and stability of Elo Not sure how to phrase this...
I am aware that Elo measures the relative strength of players.
Let's assume for this question that there is such thing as an absolute strength in chess and that players stay at their level without improving or getting worse over time.
If there are only two people in the pool playing many games against each other their Elo ratings will settle on some value and these values are a measure of their absolute strength.
Now, if there are more than two players, I was wondering, whether under the assumptions above (absolute strength exists, no change over time), the Elo ratings would also settle on constant values or would keep on changing constantly?
For the answer, I would like to exclude chess arguments like: player A cannot deal with player B's aggressive style and scores worse than against other players of the same rating (but who play more calmly).

Basically I am wondering whether there is some kind of analogue to frustration (physics term) in the Elo system, namely that, if you have >2 players in a pool they would not happily settle on a rating.
To put it concretely, I am wondering whether the system of players ends up in a steady state of constant player ratings such that if at that point in time any two players play against each other a million games, their outcome reflects exactly their rating difference.
It is assumed that players are of comparable strength so that they have a non-zero probability to draw (or win).

No. In the general case, the ELO ratings of three people will not converge to some stable equilibrium, and here's why.
Suppose you have two players, A and B. B on average scores 66% vs A, so if they played enough games, B's ELO rating would converge to about 100 more than A's.
Now suppose we introduce player C, who scores 66% vs B on average, but never plays against player A.  If C and B play many games, their ELO difference will stabilize to about 100 as well.  If B kept playing games with A during this time, A would converge to about 100 less than B, with C about 100 more than B.
So, what happens when A finally starts playing C? For there to be stability in the ratings, we MUST have C score 76% vs A, because C is 200 ELO points higher than A.  If A scores better than that, A would gain points when playing C, causing the gap between A and B to decrease.  But then A would lose the points A gained if they started another long series with B.  In this case, the three ELO ratings are not only a function of how well they play against eachother, but also how often they play each opponent - clearly not an absolute rating in any sense.
So this begs the question, if B beats A 66% of the time, and C beats B 66% of the time, should we automatically assume that C beats A 76% of the time, as the ELO functions imply?  That doesn't sound too crazy, but for the 3 body ELO problem to be stable, this implied score would have to be accurate for ANY pair of ELO gaps between A-B and B-C.  There aren't any assumptions in the ELO model that this transitivity should work.

They wouldn't stay totally still because ratings vary after every game but in the long term they'd tend to converge to the same value


How is this stalemate? My friend played this game as white and wants to know how this is a stalemate. I do not know much about chess and both of us would like to know more about this rule.

k7/2Q5/8/P2P4/1R6/8/2P3PP/6K1 w - - 0 1

1.Rb6 1/2-1/2

Stalemate is defined as the player's whose turn it is to not be in check, & cannot make a legal move (black's only piece, the king, can only move to squares where it will be in check, which is illegal).

By playing Rb6 (or possibly Rxb6), your friend walked into that exact situation. Essentially, she blocked off all the squares the King could move to, which is stalemate (& the result is a draw). It might have been a mistake, or it could have been the best move given the situation.

Additional discussion beyond the original question

If there was a black queen on b6, your friend capturing (Rxb6) was the best move, because they would have to get out of check. They can capture with the queen, the rook, or the pawn, but all three lead to stalemate (a draw is all they can hope for here). If they try to move the king out of check, black takes their queen and has a tiny advantage going into the endgame.

Interestingly, if there was a black bishop on b6 threatening the king, the best move would be to move the king and give up the queen. A rook plus several pawns will eventually overpower a lone bishop in the endgame.

If your friend captured anything other than a queen or bishop on b6, that was a blunder that forced stalemate from a winning position.

If there was no black piece on b6, your friend also had the game basically won. They could have finished it with:

1.Rb8# (Rook moves to the dark square up and to the left of the Queen, and checkmate)

Another option:

1.Qb8# (Queen moves to the same square, and checkmate) among other moves.

The last two cases are perfect examples of how chess can punish or reward you in one move; you can be totally winning and then end up with what is essentially a tie because you messed up.

Well, Black's king only has the squares a7, b7, and b8 available to it. Since the queen is guarding all three squares and black doesn't have any other pieces, it's stalemate.

If you don't know what stalemate means, either read desertdogv's comment or go to here: https://en.wikipedia.org/wiki/Stalemate


Are there any moves in the opening stage that are perfectly sound but not book moves? In the opening stage, are there any moves that are perfectly sound but are not book moves? Here a book move, is defined in Wikipedia as follows:

  Opening moves that are considered standard (often catalogued in a reference work such as the Encyclopaedia of Chess Openings) are referred to as "book moves", or simply "book". Reference works often present move sequences in simple algebraic notation, opening trees, or theory tables.

By a sound move, I mean a move that is completely reasonable in a certain opening position and does not create any weaknesses. (There may be a better definition, but you probably know what I mean.)

Obviously, you are not the first chess player to think about alternatives to the 'book moves'.

I think it is a solid assumption that all possible moves that deviate from the book move have been considered by someone already, and probably by someone with some playing strength.
So either those moves are good enough (equivalent) to 'book moves' and therefore they would have made it in the books by now, or they are (considered) at least slightly inferior.

If you consider playing an inferior move, you will have to balance the expected 'loss' from the inferiority against the potential 'gain' from forcing your opponent into a non-book variant (which you have analyzed in depth before, and he probably didn't). Depending on his strength in 'book openings' compared to his strength in 'think-yourself', this might be a good deal for you or not.

Note that this is not an uncommon idea - nearly all chess players I know have taken this approach from time to time, and more or less successful. Try it, but don't expect your opponent to be shocked out of his mind.

Depends what you mean by sound.  And what book you think is the authority.

Could a computer beat that move?  Maybe.

Would a person beat it? Much less likely.

There are many playable moves that are not in the book.  I found an absolutely sound one that is not in the book and always gives some advantage.  I also found an excellent one for time limited OTB play that gives a good winning percentage.

Eventually every good move will be played and should end up in the book.


What's wrong with Long castle in accelerated Dragon being white? What's wrong if white move to Castle long(0-0-0) in Accelerated dragon?

In the normal Dragon, the most dangerous system is the Yugoslav attack.  Current theory shows that Black can resist the attack with a pawn sacrifice and maintain the balance.  In the Accelerated Dragon, Black saves a move by moving the d pawn to d5 in one move.  This allows Black to gain a dangerous initiative.  With a Rook on the c file and the Bishops on g7 and f5, White must defend carefully.

1.e4 c5 2.Nf3 g6 3.d4 cxd4 4.Nxd4 Nc6 5.Nc3 Bg7 6.Be3 Nf6 7.Bc4
O-O 8.Bb3 d6 9.f3 Bd7 10.Qd2 and White will castle queenside (probably on the next move).  Note my comment about the necessity of playing this move order.


How can I generate legal random chess setups? Is there a free online website that attempts to generate "legal" random chess setups X amount of moves into the game?

I stumbled upon Chess Hero.  It looks very nice, but it is not online.  Per the website:

You supply a set of PGN files
The program picks random positions from the PGN files and challenges you to guess the best move computed by a chess engine
On every attempt you are given a penalty (the difference in score between your move and the engine best)

The software can be found here.

How about using live games from lichess? Here is an example call to the server. See the docs for pulling a list of users currently playing.


What is perfect play? What exactly is perfect play? Can there can be multiple perfect plays, which sounds quite contradictory? If perfect play is known for all openings then why would a player play anything other than that?  Such a thing would make all high level games futile because then players would intentionally divert from perfect play in order to just create a show or something similar.

In the context of game theory, perfect play involves playing truly optimal moves.  Specifically, if the game state is a (theoretical) win for the player to move, perfect play would be a move that both preserves that state (eg keeps the game a winning state) and minimizes the number of moves remaining until victory.  If the game state is a draw, perfect play preserves the draw.  If the game state is a loss, perfect play cannot improve the theoretical outcome, but instead maximizes the number of moves until defeat.
Perfect play is, by definition, known for solved games like Tic-Tac-Toe.  Chess is not yet solved, so in most board positions, perfect play is not known.  For some situations, for example positions with 7 or fewer total pieces on the board, we have endgame tablebases which have perfect play recorded.  Also, for positions with forced checkmate in sufficiently few moves, engines can calculate perfect play on-the-fly by simply looking at all possible moves and responses and choosing one that gives checkmate the fastest.  Perfect play is not (yet) known for chess openings.  If chess were solved and perfect play were widely known, then it is possible competitive chess may die.
There can be multiple perfect moves for a given board position.  For example, if there are two different moves that immediately checkmate the opponent, both are perfect.  Playing around with endgame tablebases, it is fairly common to find positions where multiple moves lead to checkmate in (say) 18 moves.  If the game is a theoretical draw, often many moves preserve the draw.  All of these moves are perfect from a game-theory perspective, though some may give better practical chances than others.

I am not sure whether there is a single definition of "perfect play".
The answers so far considered perfect play separately for the winning or losing player. In this sense it is often used in the negative sens: white's position is lost, even with perfect play
However, "perfect play" can also refer to the combined play of both players. As such it is what you get if the winning player is minimizing DTM (depth to mate) while the losing player is maximizing DTM. So basically what a minimax engine does.