What is the lowest chess title you can get? I am not a pro chess player or anything, but I want to get some kind of chess title. What is the lowest ranking I can get to earn a chess title?

According to this Wikipedia entry, the lowest FIDE title is Candidate Master (CM), which requires an ELO rating of at least 2200. Obviously national chess federations offer their own titles, often with lower requirements.


What are the "great injustices of chess"? Edmar Mednis stated that in KNN vs K endgame, the inability to force checkmate is "one of the great injustices of chess". The phrase "one of" seems to indicate there are other injustices in his mind.

So, what are other great injustices of chess?

It is probably not only about position, but how about playing for 7 hours, and you are positionally killing your opponent, and you slip up, throwing away all that work?

Here are a couple positions that still probably qualify:

 [FEN "7k/7P/8/6K1/4B3/8/8/8 w - - 0 1"]

You would think that white should be able to win, but no.

Or black here.

 [FEN "6K1/5P2/6q1/8/8/8/1k6/8 w - - 0 1"]

 1. Kh8=


Can black get a stalemate? Can Black somehow get a stalemate against the White King-Queen combination or should he try to save his pawn as long as he can?

8/8/5K2/4Q3/4p3/3k4/8/8 b - - 0 1

No way. I would resign if I were Black. This is a hopeless position - game over. Anybody other than a total beginner would win for White.

However if:

Black's pawn is a rook or bishop pawn
Black's pawn is close to promotion
Black's king is close to the pawn
White's king is far away from the pawn

It'd be possible to draw by stalemate.

  https://chess24.com/en/read/news/7-stalemates-every-chess-player-needs-to-know

Note: colour reversed in the examples.

King + rook pawn vs. queen

7K/7P/6q1/8/8/1k6/8/8 w - - 0 1

King + bishop pawn vs. queen (variation)

7K/5P2/6q1/8/8/3k4/8/8 w - - 0 1


What was Bobby Fischer's actual chess strength during the 1992 re-match vs. Spassky? As title above, what was Bobby Fischer's actual chess strength during the 1992 re-match vs. Spassky, apart from all his already legendary past achievements?

From wikipedia:

  Fischer's score of 17½ out of 30 (counting draws) against Spassky, rated 2545 at the time, gave him a performance rating of 2645, which would have put him at No. 12 in the world on the July 1992 list.


Would a piece that moved like a king – but could be captured (and could be moved en prise) – be considered a major or a minor piece? I could be wrong, but it seems like the major determinant of whether a piece is a major piece or a minor piece is whether a king and one of that piece can force checkmate on a lone king. Would this be possible with a king and one of these hypothetical pieces? (Or is that not actually the determinant of what is a major piece and what is a minor piece?)

This piece is widely used in different fairy chess variants. It appears under several names, including Commoner, Guard and Man / Mann.

While the table in the Wikipedia article also linked to in @Allure's answer states it's worth about four points, the article itself limits that value to the endgame:

  In the endgame, where there is usually little danger of checkmate, the fighting value of the king is about four points (Lasker 1934:73). In the endgame, a king is more powerful than a minor piece but less powerful than a rook. Julian Hodgson also puts its value at four points (Aagaard 2004:12).

On the other hand, the Wikipedia article about the fairy chess piece says

  A man is approximately equal in strength and value to a knight, generally.

That would make it a minor piece. It might depend on the board size (it's less effective on large boards, and worth much more on small boards) or the other pieces available to the players.

  it seems like the major determinant of whether a piece is a major piece or a minor piece is whether a king and one of that piece can force checkmate on a lone king

That's close to the definition I've heard: a major piece is one which can cut off the enemy king from one side of the board. Rooks and queens can do this, but this non-royal king cannot.

On the other hand, there is a basic situation where this piece is even stronger than a rook. King + rook lose against king + queen, but king + commoner is a rather simple draw.


For those who play the Catalan Opening, what are typical responses to the KID and slav defense? I'm trying to form a 1d4 repertoire (exculsively 1e4 player) around the Catalan Opening. What are some lines that Catalan players play against the KID and slav defense(it seems the normal catalan setup isn't very effective against the slav?). I know this is an open question but I do want lines in the spirit of the Catalan if possible. Thanks.

This is the exact situation where I found myself and I decided to employ
the following move order/repertoire to keep me in the spirit of the Catalan.

King's Indian defence

Against the King's Indian Defence you can use the fianchetto variation (which requires studying the Panno variations from the black side), which is actually quite solid and positional.

[fen ""]

1.d4 Nf6 2.c4 g6 3.Nf3 Bg7 4.g3 d6 5.Bg2 0-0 6.0-0 Nc6

The above can be met in many different ways: there are 7.h3 lines, 7.Nc3, 7.Qc2 and so forth (you should dig into a little theory here). Notice that 3.Nf3 avoids forcing Grünfeld lines that could occur after 3.Nc3 (3...d5 4.cxd5 Nxd5 5.e4 Nxc3 bxc3 6.c5) because there is in fact no Knight on c3 to be exchanged after 5.e4.
The fianchetto variation moreover avoids the automatic plan by Black in the standard variations of the King's Indian (Mar de la Plata) with f5-f4-g5-g4, as the construction
with g3-Bg2 by White makes it really hard to sac-sac-checkmate the King.

Slav

To be honest the best way to meet the Slav is to play the main line, as it gives
White always a slight edge and if well played Black must defend (though it is by
all means very robust and solid for the second player). Here it is important to
go 3.Nf3 instead of 3.Nc3 to avoid the Winawer gambit 3...e5 (well, unless you want to play against it and feel comfortable).

[fen ""]

1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 dxc4 5.a4 Bf5 6.e3 e6 7. Bxc4

and the standard plan is to play Qe2 and then e4-e5 (at the right moment) followed by Bd3 and attack on the Black King. There are fianchetto lines against the Slav as well, however, if you really feel the need to play fianchetto all the times.


Why is a 0x88 chessboard array of size 128 bytes when 0x88 is decimal 136? I am starting to look at chessboard representation with the 0x88 hex array board rep, but I'm getting confused! Please help me understand it properly!

The 0x88 chess board representations I have seen as examples around on net resources say it can be thought of as representing a 16x8 2D array (size 128 and so is used as 2 boards side by side to check off board moves etc).

However, afaik, hex value 0x88 is equivalent to 136 in decimal (10001000 in binary) so why is the array size not size 136 (136 bytes)?
I must be overlooking something simple with this. I apologise for this and will no doubt feel very foolish when I find what mistaken thinking my brain is stuck with over this!

I am grateful for any helpful replies,many thanks

0x88 is just the name of the system.  The actual length of the board array is 128.

The name comes from the fact that a bitwise AND can be performed the index of a square (range is 0 to 127) and 0x88.  If the result is non-zero, then the square is not on the board.  This happens because 0x88 is 10001000 in binary and every square on the board will have the form 0xxx0xxx.

Another benefit of the system is that all of the legal squares can be trivially constructed in octal notation.  For example, d4 is 0x33 assuming that 0x00 is the lower left of the board (both d and 4 are the 4th square from the edge, so 3 in a zero-indexed array).

See https://chessprogramming.wikispaces.com/0x88 for more information about this system.


Losing the queen and then winning the game Many years ago, I was on a mountain with some people. I was very young then, between 15 and 17 years old, I think. Some older people came and one of them started to play chess with me.

I cannot recall all the details, but at one moment in the game he captured my queen and I continued to play without it. Besides being without queen, he might have had 1 or 2 of my pawns and a bishop. I also had 1 or 2 his pawns, along with 1 or 2 of his bishops.

Then I started to play very smartly, and, somehow, I manged to capture his queen with a trap made by using rooks and knights. I won the game after that.

Obviously, this is not a question about the particular game I played on the mountain. It is more about, if someone loses his queen at the beginning of the game, what are the tactics to trap and capture the other player's queen?

And also, what is the actual strength of a queen? For example, is it generally better to be without queen or without two knights and a rook but with a queen?

I would like to know more about tactics when some player lost some important pieces, but played so well that he won the game. Are there any tricks that can be used here? I am also interested in such a game in which one player loses their queen, but the other one still has theirs.

Losing a queen early on without any compensation or counterplay means almost certain defeat against anybody except for absolute beginners.

There is a certain "point system" which can be used to evaluate a position:

Basically you assign points to certain aspects of the position, like material, piece activity, king safety, space advantage, etc. Adding all those points (with weights depending on the aspects), you come up with a final number, for instance -2. The sign (-) means black is better and the number 2 means that all other things being equal, black could be up by 2 pawns. Of course it could also mean that material is equal and black has much more active pieces, etc.

Just for the material aspect the points assigned to the pieces is usually pawn: 1, knight/bishop: 3, rook: 5, queen: 9 (see this for details) or thereabout.

While this point system is used by computers, for practical play it is not really relevant. I don't know any decent player who would start adding numbers to assess a position.

Still you can use it to answer your question...

Looking at games of top players, within an evaluation of roughly -1 to + 1, i.e. at most a pawn up (all other things being equal), the game usually ends in a draw.

Around +-2, the game would usually be lost/won at GM/IM level, though people might still fight for a while depending on the position.

Around +-3, good players would typically resign immediately.

Of course there are exceptions to this rule and particularly in very tactical/wild positions with open kings and attacking potentials, there could be chances for the losing side.

Still it could give you an idea of what losing a queen (value 9) means...

  I would like to know more about tactics when some player lost some important pieces, but played so well that he won the game. Are there any tricks that can be used here? I

The word you mean is "strategy" not "tactics". As outlined above, most people would resign in a situation like you describe. Still, if you think your opponent is weak enough to continue fighting there are a few things you can do to increase your chances:

keep many pieces on the board (don't exchange pieces): this increases the potential for tactics
keep the position complicated: typically this means open positions with lots of piece activity
start a direct attack on the enemy king
if time is limited try to force your opponent getting low on time, e.g. by moving quickly, doing unusual moves, etc.
play for tricks/tactics (you really should never do this in chess because it is not how you play chess beyond a certain level...)


Should a chess engine be aware of opposite-side castling? I often hear chess experts and chess articles say that when opposite side castling occurs on the board that it is important to launch an attack on the enemy player as fast as possible. Up to the point where giving up a couple pawns or a piece could be justified.
In other words, it seems like castling opposite sides changes the dynamic of the game. How much this change is I'm not sure of. So here is my question:

Is opposite side castling significant enough that a chess engine should think about such positions differently from how it would normally?

For example, a chess engine could lower the importance of material and up the importance of king safety in its evaluation when opposite castling occurs.

I'm pretty sure Stockfish doesn't have explicit code that handles opposite-side castling. What it does have is:

Some kind of "menace" score for enemy pawns advancing against our king. The closer they get, the more dangerous Stockfish thinks they are.
Some kind of "pawn shield" score for friendly pawns in front of our king. The fewer there are, the more dangerous Stockfish thinks the position is.

Therefore you get kind of a balancing act: if we castle on the same side, then we could advance our pawns against their king (getting the "menace bonus"), but it would reduce our pawn shield (and therefore losing the "pawn shield bonus"). The converse does not hold in opposite side castling, which therefore encourages the engine to push pawns against the enemy king.
Of course, the details are more complicated than this, but that's the gist.


Automatically claiming draw when low on time Suppose X and Y are in an endgame:

X has a rook and 400 seconds.
Y has a rook and 40 seconds.

Y obviously cannot claim draw because X can theoretically win, even
though a minimally careful play would result in a draw.
X will play to make Y's time run out, but has to avoid the 50 move draw and
the threefold repetition draw.
Now, since Y is hard pressed on time, he may not notice that a position has
been repeated three times. More inexperient players may even overlook that
the 50 moves have been made. In this scenario, will Y actually have missed the
chance to get the draw? Or can Y tell the arbiter that he wants to have the
draw if any of those events occur, even if Y misses it?
Lichess has an option to claim draw on threefold repetition when time remaining < 30 seconds, thus I'm wondering if there is something of the sort for on the board games.

I'm wondering if there is something of the sort for on the board games

The closest thing to this according to the latest FIDE Laws of Chess is article 9.6:

9.6 If one or both of the following occur(s) then the game is drawn:
9.6.1 the same position has appeared, as in 9.2.2 at least five times.
9.6.2 any series of at least 75 moves have been made by each player without the movement of any pawn and without any capture. If the last move resulted in checkmate, that shall take precedence.

However this process is not automatic. For either of these scenarios to play out then either the arbiter has to be watching and counting or the moves have to be recorded by at least one of the players and then brought to the arbiter's attention.
In general a game is drawn after 3 repetitions or 50 moves without a capture or pawn move only if one of the players makes a valid claim backed up by a recording of the moves.
See:

9.2.1 The game is drawn, upon a correct claim by a player having the move, when the same position for at least the third time (not necessarily by a repetition of moves):
9.2.1.1    is about to appear, if he first writes his move, which cannot be changed, on his scoresheet and declares to the arbiter his intention to make this move, or
9.2.1.2   has just appeared, and the player claiming the draw has the move.

and

9.3 The game is drawn, upon a correct claim by a player having the move, if:
9.3.1 he writes his move, which cannot be changed, on his scoresheet and declares to the arbiter his intention to make this move which will result in the last 50 moves by each player having been made without the movement of any pawn and without any capture, or
9.3.2 the last 50 moves by each player have been completed without the movement of any pawn and without any capture.

but note:

9.4 If the player touches a piece as in Article 4.3, he loses the right to claim a draw under Article 9.2 or 9.3 on that move.

So, you can't retrospectively claim a draw under 3 fold repetition or the 50 move rule.
Note that if there are no increments then in special circumstances you may be able to claim a draw when low on time in endgames like KR vs KR.
Here is what the rules say:

III.2.1 The Guidelines below concerning the final period of the game including Quickplay Finishes, shall only be used at an event if their use has been announced beforehand.
III.2.2 These Guidelines shall apply only to standard chess and rapid chess games without increment and not to blitz games.

Important to note that these rules never apply to blitz games, only standard and rapid. Also important to note that they only apply if announced beforehand. This will rarely happen.
Then:

III.4 If the player having the move has less than two minutes left on his clock, he may request that an increment extra five seconds be introduced for both players. This constitutes the offer of a draw. If the offer refused, and the arbiter agrees to the request, the clocks shall then be set with the extra time; the opponent shall be awarded two extra minutes and the game shall continue.
III.5 If Article III.4 does not apply and the player having the move has less than two minutes left on his clock, he may claim a draw before his flag falls. He shall summon the arbiter and may stop the chessclock (see Article 6.12.2). He may claim on the basis that his opponent cannot win by normal means, and/or that his opponent has been making no effort to win by normal means:


UCI engine state notion Hi guys I have a problem with using stockfish engine which is using UCI protocol. I wanted to play black and the computer white. But so far I think that uci engine has no notion of state and it gives me the same best moves over. I wanted to know if there's a way to set UCI engine to play as black or white so when am playing as white and gives it move in FEN string notation. It will suggest a move to black.
I have the following log below:
...
option name Emergency Move Time type spin default 30 min 0 max 5000
option name Minimum Thinking Time type spin default 20 min 0 max 5000
option name Slow Mover type spin default 80 min 10 max 1000
option name UCI_Chess960 type check default false
...

uciok
setoption name Hash value 128
ucinewgame

position startpost moves Ng1f3
info depth 1 seldepth 1 score cp 82 nodes 27 nps 27000 time 1 multipv 1 pv e2e4
info depth 2 seldepth 2 score cp 9 nodes 155 nps 155000 time 1 multipv 1 pv d2d4
 d7d5
info depth 3 seldepth 3 score cp 56 nodes 278 nps 278000 time 1 multipv 1 pv d2d
4 d7d5 g1f3
info depth 4 seldepth 4 score cp 8 nodes 749 nps 749000 time 1 multipv 1 pv d2d4
 g8f6 g1f3 d7d6
...
stop

bestmove e2e4 ponder e7e5

Comment : I make a move e2e4 and computer makes a move e7e5

position startpos e7e5 (based on last computer move)

go infinite
wait (5sec)

bestmove e2e4 ponder e7e5

Why is it still e2e4 ponder e7e5, the same best move as the last one. How can I set it to give a best move for black player (me). What kind of commands do i need to set here? Desperately need your help on this guys. Thanks
EDITED
Guys I really appreciate your healthy discussion over this. But I only understand a few concepts regarding UCI engine.
Here's what I have understood so far.
-> There is no FEN to PGN conversion because FEN is the positions of the chess pieces after a number of moves and its not possible to convert it to PGN because FEN doesn't contain the sequence necessary to be converted to PGN
-> PGN on the other hand contains the moves of the players in sequence so it can easily be converted to FEN
Right now my problem is that DGTs electronic board only gives FEN where I use it as an input to our application and am still researching on how I can get PGN from it. I know Fritz shows the PGN as well as other GUI's.
Any ideas on where to proceed from here?

Use the "position fen" command.

For example, take a look at http://support.stockfishchess.org/kb/advanced-topics/uci-protocol. From the example in the link, you could easily change to black's move by

"position fen rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR b KQkq - 0 1"

Simply change "... w KQkq" to "... b KQkq". The letter tells the engine which color to move for the position.

To start an infinite analysis, use "go infinite".

Please note that "position startpos" assumes a valid move sequence. Failed to do so will result in undefined behavior - it could crash, do nothing or something else.

Edited:

FEN and PGN are two different things. FEN represents a particular position on the board. PGN is the whole game. You don't convert from one to the other. Talking about conversion is meaningless.
You don't do "position startpos FEN1 FEN2 FEN3 FEN4", please read the UCI specification again. You give the moves with the startpos command, not the position itself.
Stockfish doesn't care how you tell it to reach a particular position.
There is a comment that giving a startpos would be a better way to start a game. But why? Think again, and ask yourself, why?? Why would you think giving a command like "startpos e2e4 e7e5 .... ..... (20 more moves) .... .... " is better than simply giving out the FEN of the position? You typically use a chess GUI to interact with an engine, and the chess GUI must have its own chess-board validator. It's quite easy to generate a FEN string from a validator. However, generating a sequence of moves from the initial position would involve looping over all moves, the complexity of the operation is O(n) where n is the number of moves in the game. Furthermore, you'd have to reserve extra buffer to save the long string. The engine would then have to parse the long string, again this is a slow operation. The startpos is strictly unnecessary.

Edited Again for the poster

PGN can technically be converted into a sequence of FEN positions, but it's meaningless. Nobody does that. Your confusion is all based on the fact that you don't know how to interact with an engine. Don't worry, I'll guide you.

Before you can do anything, you'll need a board generator in your own code. You'll need it because you need something to tell Stockfish what to do, and the only way to do that is with a board generator. Every single chess GUI has it.

Make sure you can use your board generator to convert your position to a FEN or a sequence of moves from the initial position. Either way works, you don't need a PGN. I repeat, you DON'T NEED a PGN to interact with a chess engine. Forget about the PGN, period.

Now, it's easy. You make a move on your physical chess board. Your board generator updates the move and sends the update to Stockfish. The update could be a FEN string or a sequence of moves from the initial position. It doesn't really matter which way you go. I recommend the FEN approach because it'll be easier for you to debug your UCI session.


What is White's main plan in Sicilian Keres variation? I want to learn a new opening in the Sicilian defense called the Keres variation. What is White's main plan here?
[FEN ""]

1. e4 c5 2. Ne2

Disclaimer: there might be other ideas too.
I used to play this some time ago against sicilian. My idea was that I liked closed sicilian positions (2. Nc3) if black did not play the "main" setup against it (that is, 2. ... Nc6, 3. ... g6 etc). So with Ne2, I still could play the closed variation against, for example, 2. ... e6 and 3... d5, and after 2. ... a6, but if black replied 2. ... Nc6 I could play 3. d4 ( or 4. d4) and return back to the "open", more sound sicilian. What white gains is a little bit of flexibility, and a chance to confuse the opponent if black has an inconsistent repertoire. I knew one guy who played d6-a6 setup against open sicilian and e6-d5 against closed one, so Ne2 was very confusing against him.


how does a uci engine draw or resign? I am writing a UCI chess AI/engine. It has the ability to draw and resign. How do I communicate this to the uci chess interface? what string shoud i send back to the GUI?

UCI chess engines don't offer/accept a draw, nor resign a position. This is the GUI's responsibility.

You are welcome to add new uci options (setoption and option) for your engine, but don't expect universe UCI support.


Is e5 fully playable in the following positions? Can someone provide computer analysis that confirms or refutes the correctness of ...e5, played in the below positions.

First position:

[Title "Black relies on tactics to carry out freeing break"]
[fen "rn1qkb1r/pp3pp1/2p2np1/4p3/3P4/6P1/PPP1NPBP/R1BQK2R w KQkq - 0 1"]

1.dxe5 Qxd1+ 2.Kxd1 Ng4 3.Ke1 Nxe5

Second position:

[Title "White loosened control over center so Black tries e5 break"]
[fen "r2qkb1r/pp1n1pp1/2p2np1/4p3/3P4/6P1/PPP1NPBP/R1BQ1RK1 w KQkq - 0 1"]

My computer is very old and weak, so I can't be confident in its analytical powers. If you could provide concrete lines that refute or verify the correctness of ...e5, played in both diagrams, I would highly appreciate it.

Thank you.

A quick analysis of the first position shows that 0...e5 was playable in that there was not a fundamentally better choice.  Stockfish would prefer 0...Nbd7 but the resulting score is only .2 points better than 0...e5.  Those fractions add up after a while, but if one is looking to uncramp one's game, it could be a bargain.  7 hours of grinding shows that neither side gets much of an advantage after 0...e5 1. O-O. The score settled on about .75 in White's favor.

Here's the continuation at 15 minutes per move. I think this shows that 1... e5 is playable and leads to a sharp game.  White retains a slight advantage the whole time.

[fen "rn1qkb1r/pp3pp1/2p2np1/4p3/3P4/6P1/PPP1NPBP/R1BQK2R w KQkq - 0 1"]

2.O-O Nbd7 3.b4 Be7 4.Rb1 O-O 5.c4 exd4 6.Nxd4 Nb6 7.b5 c5 8.Nb3 Qxd1 9.Rxd1 Nxc4 10.Bxb7 Rad8 11.Re1 Bd6 *

Here's the second position. I didn't see ALNS's message until this morning, so I thought I might as well post the results. There is a deviation in the moves, probably the result of me using the computer last evening while the program chugged in the background.

[fen "r2qkb1r/pp1n1pp1/2p2np1/4p3/3P4/6P1/PPP1NPBP/R1BQ1RK1 w KQkq - 0 1"]

1.b4 Be7 2.Rb1 O-O 3.c4 exd4 4.Nxd4 Nb6 5.c5 Nbd5 6.Qb3 a5 7.a3 Qd7 8.Bb2 Nc7 9.Rbd1 Nfd5 10.Nc2 Qg4 11.Bf3 Qf5 12.Rfe1 Rfe8 13.Be4 Qg4 14.Qc4 Qh5 *

The machine tallies this position as anywhere from .55 to .70 (through the next 16 moves!) depending on the exact variation being calculated. That is, there is no appreciable change in the score in the entire variation. It would seem 0... e5 is a viable move.


What is the minimum number of pieces needed in a chess set to account for all possible promoted pieces? How many pieces would be needed in a chess set where all possibilities for promoted pieces are included if pawns are no longer used after they promote?

Let's count.
Starting set

2 rooks
2 bishops
2 knights
1 queen
1 king
(8 pawns)

Max promotions

8 rooks
8 bishops
8 knights
8 queens

Total
In total you would need 40 pieces and 8 pawns for each color, so 96 units for black and white together.
Edited to bullet format to "look" better.


Why is Jovanka Houska introduced as a WGM when she holds the more prestigious IM title? I've been watching the Champions Chess Tour and find it strange that Jovanka Houska is always (at least whenever I am watching) introduced as a woman grandmaster. Now I have absolutely no problem with her holding that title, but according to Wikipedia she also holds the more prestigious international master title (in addition to being the highest-rated active British womans player). Why do they not introduce her by also mentioning her higher achievements?

I think an important aspect to consider is the audience of the show. For the Champions Chess Tour, chess24 has two English language shows; one with Houska and David Howell targeted to a more casual audience, the other with Tania Sachdev and Peter Leko that is aimed towards an audience that is more familiar with chess terminology and concepts.
I think a decision was made that the title of "international master" is too unfamiliar to a casual audience. Everybody knows a grandmaster is "someone who is great at chess", but only people who know chess lingo know what an IM is. I think either the producers of the show or Houska herself decided to go with the easier to understand "Woman Grandmaster" title because the viewers would better understand it to mean "a lady who is great at chess".
It is interesting to note that Tania Sachdev, herself also both an IM and WGM, is introduced as an IM on the show targeted to the more technical audience.


Using the king to prevent castling What is a more difficult problem which involves using the king to prevent castling than the following problem?

White to play and win:

[FEN "r3k3/5p2/2K2P1P/b1N1P2P/8/8/4n3/8 w q - 0 1"]

In this famous problem by H. Hultberg (1944), the white king castles to prevent Black from castling:
[FEN "r3k2/1p1p2p1/2pP3p/8/8/5R2/PPPP4/4K2R - - - 0 0 "]

White to mate in two moves.
According to chess problem conventions, castling is presumed to be legal unless it's provably illegal. In this position, you can prove that at least one player has lost the right to castle, but you don't know which one. (If the white rook on f3 came from a1, the white king must have moved to let it out. If the rook on f3 is a promoted piece, it must have visited a8, e8, or f8 before escaping the 8th rank, so the black king or rook must have moved.)
1.Rhf1? fails to 1...O-O-O.
1.O-O! and 2.Rf8#, as Black is now unable to castle.


Why is 7. f3 so ubiquitous in the Yugoslav Sicilian? I'm a mid-level player just starting to systematically study openings, and I'm wondering why it is that after the signature Yugoslav initiation 6. Be3 by White, and the certain follow-up 6. ... Bg7, it seems that virtually all masters (~95% according to lichess) opt to play 7. f3.

Specifically, I've been reading John Emms' Starting Out series on the Sicilian, and the only mention he gives of this move is that it prevents an "annoying Ng4." Why is it all that annoying? For example, let's say I play 7. Qd2 first, then Ng4 by Black, chasing the bishop to g5 for fear of exchange, with h6 by Black forcing Bh4:

rnbqk2r/pp2ppb1/3p2pp/8/3NP1nB/2N5/PPPQ1PPP/R3KB1R b KQkq - 1 9

Sure, the bishop has had some cardio in the opening, and it no longer looks like the typical Yugoslav exchange of Dragon bishops is going to happen, but it at least looks playable. Stockfish 25ply rates it at +0.3. This is equivalent to how it rates the orthodox Yugoslav tabiya:

r2q1rk1/pp1bppbp/2np1np1/8/2BNP3/2N1BP2/PPPQ2PP/2KR3R b - - 6 10

What am I missing?

Objectively speaking, you're probably right: 7.Qd2 seems fine and after 7....Ng4 white can still hope for an advantage after 8.Bg5 Nc6 9.Nb3.

However, after 7.Qd2 Nc6, black does threaten Ng4. So, white should play 8.f3 anyway, also because it is part of his plan. As a result, we transposed to the main line of 7.f3.

Therefore, white doesn't gain anything by playing 7.Qd2 first. Actually, it only gives black an extra option: 7....Ng4.


How to tweak a chess engine like SF to return a variation which is only slightly better than your moves? By default, engines return the strongest variation(s) they calculate. I was wondering if there is a way to tweak an open source chess engine to show a move from their MultiPV which is slightly better than or equal to your moves. Let's say the evaluation stays only +2 consistently through the game. Instead of the strongest move in a position, the engine is retuning back the move with +2. Is there a way to do this?

[edit 3.10.2019] in case of a blunder (e.g. +3 jump in the engine evaluation, the engine can keep the difference and continue the game with +5 instead of +2).

[edit 4.10.2019] I found that on https://lichess.org there are levels for SF. Right now,  level 5 corresponds to ca. 1700 elo, level 6 is 1900, level 7 is 2200. This satisfies my needs and closes my question. Thank you

Ok, so say the engine plays a move with white and values the position as +0.50 (slightly better for white). So now the human plays as black, and blunders a bishop. The engine now values the position as +3.50, but you want to play a move as close as possible to +0.50, v. g. +0.60. Is it what you're looking for?

In that case it seems the way to go is (from the POV of the engine); "the position after my last move was +0.50, so in the current position, if a move that improves that eval exists, I must play the one closest to +0.50. Otherwise (there isn't a move that improves my eval after my last move), play the best move available."
If this is your idea, I guess this is doable, and for someone who develops their own chess engine probably shouldn't be hard to code.

Maybe the idea can be improved. For example, if you blunder a bishop, probably it's a good idea the engine to grab the bishop than to play something really stupid.

In any case, I think it's definitely doable, probably with some refinement. (For example, it's not the same blundering a bishop in one than losing a bishop after a 10 moves combination; in the first case, IMO, the engine should take the bishop, but in the second one it should chose a sub-optimal move).


Where can I see the recorded chess matches? I want to know if there is any web site that maintains the recording of the famous chess tournaments. I am not looking for the video recordings, but the recording of the moves. For eg.  I am currently looking for all the recent matches held between Carlsen and Anand in November, 2014.

This Week In Chess is probably the best place to go for those. New game files are posted weekly. Though in the case of Carlsen-Anand 2014, it's probably available from dozens of places, including the official website of the match itself: http://www.sochi2014.fide.com/results/


What is the Elo rating of a chess computer that can only look 1, 2, 3, ... moves ahead Has anyone calculated the average Elo rating of a chess computer as a function of the number of half moves or plys ahead it can look. I realise that the Elo is also a function of the choice of move then taken which may differ from engine to engine.

This is an area that academic can write papers on it. The relationships is complicated and might not be quantified.

Essentially, it's a non-linear relationship where the improvement is most obvious in shallow depth. The benefit diminishes as the engine go deeper and deeper in the search.

Reference: https://chessprogramming.wikispaces.com/Depth

Look for the "Diminishing Returns" section and you'll know more.


Is the Poisoned Pawn variation of the Najdorf (7... Qb6) considered some sort of refutation of 6.Bg5? As title above, is the Poisoned Pawn variation of the Najdorf considered some sort of refutation of 6.Bg5, and the reason why 6.Bg5 is rarely seen at top level these days?

The problem with Bg5 is mainly that black will usually be better prepared than white in the messy poisoned pawn. He either doesn't play it or he knows it. On the other hand imagine Be3. There black is quite predictable as not following the main lines is too dangerous. White has a lot of good systems to try so he has much easier life. Objective quality is not that important part of decision process what to play as Be3 Najdorf, Bg5 Najdorf as well as Queen's Indian end virtually always in draw in correspondence games. To me Be3 Najdorf seems so unpractical for black that I would prefer dragon, Sveshnikov or classical over it. Knowing that with white, who would try so hardly to get the Bg5 mess against well prepared opponent?


Can't understand a sentence from Nimzowitsch's Chess Praxis In the chapter "Centralization" of his Chess Praxis, Nimzowitsch writes

  The mechanics of centralization can be seen in the way that, after the necessary restraint of a possibly mobile opposing pawn center, we draw the noose tighter and tighter around the central squares...But if we manage to make this long-range action effective and establish some of our pieces in the center, then we should be really pleased with the success of our policy of centralization.

What does he mean by "drawing the noose tighter"? So far, I have come to conclusion that "drawing the noose tighter" means the "long-range action" mentioned in the next sentence and therefore some sort of pressure on the center exerted by long-range pieces.

After re-reading the chapter Centralization I think that Nimzowitsch meant the following:

First you restrict the opponent's pawns
Then you start impacting the opponent's center from the distance using long-range pieces (the so-called "long-range action")
Then you start closer-range actions against the opponent's center (i.e. "you draw the noose tighter"), e.g. by occupying some central square


What are all the possible combinations of openings which work well together? (like the Slav+Caro-Kann combo) One well known very good combo is the Caro-Kann + the Slav:

The main objective of both of these openings is to develop the light-squared Bishop to f5 before it gets locked inside the Pawn chain.
They tend to lead to roughly similar Pawn structures.
On average they both tend to lead to positional, quiet and strategic games.
And most importantly, if you choose both of these openings, against 1. c4 you can play 1...c6 which can transpose into either a Slav (2. d4) or a Caro-Kann Panov/Pseudo-Panov (2. e4).

I would like to know what are all the other possible combinations of openings which work well together.

Enumerate as many combos as you can. But I am only interested in combos where both openings are sound.

And if possible also explain why exactly the openings work well together.

I don't think there is a single other opening combo that shares as many features as the Caro-Kann and the Slav. All the other defences against e4 lead to unique pawn structures and piece constellations that aren't easily reached from d4/c4-openings.

Just playing the same move against e4 and d4 either leads to completely different openings (Indian Defences/Alekhine, Sicilian/OldBenoni, French/Whatever) or exactly the same defence (The Modern).

That being said, there are some popular opening-combos, but they usually own their popularity to a similar attitude or character of play.

One such combo would be the King's Indian and the Dragon. The obvious similarity is the fianchettoed bishop and the aggressive attitude.

Another might be the French and the Nimzo-Indian. Both are rather strategic setups with counterplay on the queenside.

The Queen's Gambit declined and 1…e5 would be another sensible combination. The attitude is classical: Equalise first, play for a win later.


How is this retrograde analysis position legal? On his page on Harry Goldsteen's "Horse Concoction,", Tim Krabbé gives this position by "N. Höeg, 1935."
[FEN "4k3/1p4pp/p1pQ1p2/1q1pp3/8/8/1K6/8 b - - 0 1"]
[StartFlipped "0"]

With the stipulation "add 10 white rooks; black mates in 1," he then claims that "Retrograde-analysis will prove that these Rooks can only stand on a1, a2, a7, b4, c1, c2, c5, c7, d7 and f7, allowing Black to mate with Qxb4." This is the claimed solution,
[FEN "4k3/RpRR1Rpp/p1pQ1p2/1qRpp3/1R6/8/RKR5/R1R5 b - - 0 1"]
[StartFlipped "0"]

However, I don't see how the supposed solution position could be legal. All of White's pawns have promoted, but because all of Black's pawns are present they must all have captured at least once to do so. But Black has only 5 missing pieces.

White has made 6 captures. Clearly the h-pawn made at least 2, and the g-pawn 1. Meanwhile, the b-pawn made at least 1 (a7/c7), and the a-pawn at least 2 (to the b-file, then to either a7/c7). So White's c-d-e-f pawns made no captures, and thus Black's central pawn fence must have at some point had holes to allow them through. This requires 4 pawn captures, which is all that White has lost (knights and bishops).

Here is a stupid method.

[fen ""]
1. h4 Nh6 2. e4 f6 3. e5 Kf7 4. e6+ Kg6 5. f4 Ng4 6. f5+ Kh5 7. Nf3 a6
8. Ne5 fxe5 9. f6 Ra7 10. f7 Ra8 11. d4 Ra7 12. Bg5 Ra8 13. Bf6 exf6
14. Na3 Bb4+ 15. Ke2 Bd2 16. f8=R Bg5 17. hxg5+ Nh2 18. e7 Kh4 19. e8=R Ra7
20. Re6 Ra8 21. Rb6 Ra7 22. Rb3 Ra8 23. Re8 Ra7 24. Re6 Ra8 25. Reb6 Ra7
26. R6b4 Ra8 27. d5+ Kh5 28. g6 Rf8 29. Rg1 Rf7 30. gxf7 Ng4 31. f8=R Nh6
32. Re8 Nf7 33. g4+ Kh4 34. g5+ Kh5 35. Re6 Nc6 36. g6 Nb8 37. gxf7 Nc6
38. f8=R Nb8 39. Rc6 Ra7 40. Rcc3 Ra8 41. Re8 Ra7 42. Re6 Ra8 43. Rec6 Ra7
44. R6c4 Ra8 45. Rcg4 Ra7 46. R4g2 Ra8 47. Rbg4 Ra7 48. R4g3 Ra8 49. d6 c6
50. Nc4 Ra7 51. Ne3 Ra8 52. Nd5 cxd5 53. Rcf3 Kh6 54. c4 Ra7 55. c5 Ra8
56. c6 Ra7 57. c7 Ra8 58. Kf2 Ra7 59. Bb5 Ra8 60. Bc6 dxc6 61. Qe2 Bf5
62. c8=R Qe7 63. d7 Bd3 64. d8=R Bb5 65. a4 Ra7 66. axb5 Nd7 67. b6 Nc5
68. bxa7 Ne6 69. Rbe3 Nc7 70. b4 Qf7 71. a8=R Qg6 72. b5 Qg5 73. b6 Kg6
74. bxc7 Kf7 75. Ra7 Qf5 76. Rgc1 Qe6 77. Ke1 Qe7 78. Rd6 Qe6 79. Rcd8 Qe7
80. R8d7 Kf8 81. c8=R+ Qe8 82. Rcc7 Qf7 83. Re6 Qe7 84. Kd2 Qd6 85. Ree7
Qc5 86. Rf7+ Ke8 87. Rec3 Qb5 88. Qc4 Qb6 89. Qc5 Qb5 90. Qd6 Qb6 91. Kc2
Qc5 92. Kb2 Qc4 93. Rca3 Qc5 94. R3a2 Qb6+ 95. Rb3 Qb4 96. Rgc3 Qb5 97. Rc5
Qb6 98. Rb4 Qb5 99. Rgc2 Qxb4#


Fairy endgame statistics for KDDDDvKN (D=dabbaba; '2,0' leaper)? The dabbaba is a '2,0' leaper fairy piece, only able to ever reach a quarter of the squares on the board. According to the linked Wikipedia page, a quartet of them can apparently "easily" force mate against a bare king with the help of their own king; however, I'm curious whether an orthodox knight could reliably hold off the dabbaba quartet. It's effectively a 7-piece endgame, just that 4 of the pieces are weaker fairy pieces; four '2,0' leapers that can each only reach a quarter of the squares on the board versus a single '2,1' leaper that can reach any square on the board.

As for the dabbaba's aforementioned restriction to a quarter of the squares on the board, a single dabbaba can reach either ACEG or BDFH files and either odd ranks or even ranks; making the 4 dabbabas of the quartet be the odd ACEG, even ACEG, odd BDFH, and even BDFH. Assuming the 4 dabbabas are to cover their respective quarters of the board, there should be ((16^4)/8)*(60!/(60-3)!)*2 meaningfully unique KDDDDvKN positions to look at minus any where side-to-move could just take the other side's king or is already checkmated by the other side.

I was unable to generate data for exactly what you want, but I managed something with a restriction to 6x6 board. I think it's reasonable to assume that it doesn't make a big difference from 8x8 for this specific case since there are no powerful pieces on the board (with unrestricted movement distance).

Available positions are enumerated by starting from a certain position and doing moves until we can. It should give all possible positions but I'm not sure. (I respect the requirement posed by OP that all Ds have different available positions)

Code (C++17, uses a few MSVC specific intrinsics) (tuned for this specific piece types and configuration): https://pastebin.com/d6J5WHuY

Stripped WDL data:

        W               D               L
KvK     0.000000000%    100.000000000%  0.000000000%
KDvK    0.000000000%    0.000000000%    0.000000000%
KDDvK   0.620803000%    99.379200000%   0.000000000%
KDDDvK  25.666000000%   74.334000000%   0.000000000%
KDDDDvK 69.638300000%   30.361700000%   0.000000000%
KvKN    0.000000000%    100.000000000%  0.000000000%
KDvKN   0.000761905%    99.997700000%   0.001523810%
KDDvKN  0.083948400%    99.916000000%   0.000000000%
KDDDvKN 3.553240000%    96.446800000%   0.000000000%

        Longest DTM for white
            Longest DTM for black
KvK     0   0
KDvK    0   0
KDDvK   17  0
KDDDvK  57  0
KDDDDvK 63  0
KvKN    0   0
KDvKN   1   1
KDDvKN  17  0
KDDDvKN 63  0

I'm unable to generate KDDDDvKN as it would require ~32GiB of RAM (should take less than an hour though), which I don't have.

Buf overall it can be seen that around a quarter of KDDDvK games are winning for white which may suggest that there are non-trivial winning KDDDDvKN positions.

I also have more detailed logs with the longest winning line shown.
https://drive.google.com/drive/folders/1_aLMYB87zVJ9qslQxafTZNKHgXsoBnl2?usp=sharing

I have not added any persistence/querying and I don't plan to. Code is provided above.


Why is Bxh6 not preferred here? [FEN "rnb1k2r/ppppqppp/4p2n/4P3/2PP4/2PB1N2/P4PPP/R1BQK2R w KQkq - 3 9"]

I was just post-analyzing a game of mine with an engine and to my surprise in the position displayed above, it didn't even consider taking the knight on h6 as one of the top few moves.

Can someone explain me why that is? In many positions where the opponent's knight goes to a6 or h6 it's beneficial to take with an undeveloped bishop and I'm not sure why it's not here. It doubles my opponent's outer pawns which seems quite bad to me especially when he's likely to castle king side. Instead the engine prefers castling which allows the knight to go to f5 next square which seems like an OK square for the knight.

Is my dark squared bishop that important in this position or what's the idea behind this?

Is my dark squared bishop that important in this position or what's
  the idea behind this?

Yes, your dark squared bishop is very important in this position. Your opponent doesn't have one, so yours is unopposed. Furthermore you have the minor advantages of the two bishops.

Doubling your opponent's pawns isn't as big a plus as you imagine in this position. Yes, it weakens Black's kingside but it also opens the g file for his rook which could, in the short term, more than compensate.

Finally, you have some very good threats with your bishop against the awkwardly placed Black queen. They don't quite work immediately but both Bg5 and Ba3 could be very embarrassing with the right preparation. A move like Qb3 prepares both and could be a good move to start with.


Is studying computer games legal in correspondence chess? I have recently umm downloaded the Dragon Cookbook from Chessbase. It is filled with human and computer games in the dragon. The thing is, are previously played computer games allowed to be seen in correspondence chess?

On chess.com, use of books and game databases is allowed. Use of engines and tablebases is not. Your book is either a book or a game database and therefore fine.

There are also sites that don't allow any outside help (no books, no databases), and on the other hand the ICCF (the offiical FIDE-affiliated Correspondence Federation that is also completely online nowadays) does allow engine use, so it's best to always check the rules of the actual site you're using.


What merit is there to the so-called "Swiss gambit?" The "Swiss gambit" refers to the idea of intentionally lowering one's performance at the beginning of a Swiss-system tournament, to one degree or another, in order to have an easier path through the later stages of the tournament. E.g. a highly-rated player in a field could take a half-point bye in the first round (instead of a likely win) in order to likely be paired against weaker competition for the next few rounds than would have happened otherwise.

It certainly shouldn't be the case that it's always a good idea, or Swiss-system tournaments would be very poorly conceived. But depending on where a given player sits ratings-wise in the field, and the exact distribution of the ratings of players in the tournament, it is not inconceivable that such a Swiss gambit could increase a player's expected final score. Of course, intentionally giving points away at any point could obviously decrease the expected score as well. This is all I am asking for here:

  Has any serious research been done concerning scenarios in which a Swiss gambit is/isn't effective, probabilistically speaking, in the sense of raising/lowering the gambiteer's expected tournament score?

Pointers to any legitimately mathematical (and mathematically legitimate) discussions of the matter would be most appreciated, as would the creation of such in an answer of course.

I tried writing a crude pairings/results simulator, to see whether taking a bye could increase a top player's score.  When generating pairings, the program ignored pairing history and color (which I realize can matter, but I didn't want to have to program it to go back and redo pairings if there was a conflict - this is a crude simulator, not an actual pairings engine!)  But it was able to handle pairing people in a scoring category with the usual top half/bottom half method, as well as the all-important "pairing up" of the top person from the lower category with the bottom person from the higher category if there was an odd number of players in the higher score category.

I assumed a uniform ratings distribution through whatever ratings range I selected.  I used the "Standard winning expectancy" formula at the bottom of page 11 in this document.  I did not account for fatigue.  I assumed a draw probability of half of the probability that the higher-rated player would lose (for example, if the expected score was 0.75 according to the formula, I assumed a win would happen 70%, a draw 10%, and a loss 20%.  For even matches with 0.5 expected score it would be 40% - 20% - 40%.)  I set the program to run 100000 tournaments at a time, to get a good average.

The Swiss gambit pretty much always decreased a high-rated player's overall score regardless of the number of players, rounds, or rating spread (unless I set the draw probability parameter to zero, which is unrealistic.)  At best it had only a small negative effect on the final score.  Although the player's performance in later rounds was indeed better due to weaker opponents, that performance did not quite overcome the nearly half-point lost.  The top players were better off playing in all the rounds.

For example, in a simulation of an 8 round 200 player tournament, with player ratings ranging from 200 to 2000, the 2000-rated player had an average score of about 6.35 if they did not take a bye.  If they took a first-round bye, the average was only about 6.24.

However, for some small tournaments with large point spreads and a certain number of players, although the average score dropped, the probability of placing first actually increased.  For example, in a 5 round 32 player tournament with players rated from 200 to 2000, taking a first round bye decreased the average score from 4.23 to 3.95, but increased the probability of taking clear first from 33.2% to 34.7%.  I'm not sure if these are artifacts of an imperfect pairing engine, though; the exact pairings matter more in such situations.  In most of my simulations the decrease in score corresponded with a lower probability of taking first (and the decrease was somewhat larger than the increase shown here.)

Interestingly, although it also wasn't effective compared to playing all the rounds, it seems that taking a half-point in the second or even third round often gave a slightly better score than taking one in the first round, especially when the ratings spread was large (in the 8 round 200 player example, they scored about 6.26 by taking the bye in the second or third round, as opposed to 6.24 by taking it in the first round.)  The first round has a top half player against an easy opponent; why skip a game you'll almost certainly win, instead of skipping the next one where your opponent may have something of a chance?

So, overall:  The average score decreases when using the Swiss gambit.  The odds of winning the tournament might go up in certain specific scenarios, but I'd need a better program to say for sure, and if there is any such effect it's sensitive to the exact number of players.


How is White compensated in these lines of the Milner-Barry gambit? After White's sixth move 6. Bd3 in the Milner-Barry gambit line, White hasn't yet truly offered his pawn up for sacrifice yet. It's for this reason that Black will play cxd4, but not continue the exchange following cxd4, instead fortifying against a possible Bb5+ with Bd7. What if Black chooses not to begin the exchange until he can be sure to win it? After all, is usually happy to return dxc5 with Bxc5, so there shouldn't be any rush to trade off the c-pawn. Yet when I follow the "best play" by Stockfish (and uniquely best, if it is to be trusted) following 6. ... Bd7 and arrive at the following position:

[FEN "r3k1nr/pp1b1ppp/1qn1p3/2bpP3/8/2PB1N2/PP3PPP/RNBQ1RK1 b kq - 1 8"]
1. e4 e6 2. d4 d5 3. e5 c5 4. c3 Nc6 5. Nf3 Qb6 6. Bd3 Bd7 7. dxc5 Bxc5 8. O-O

I see White has traded away one center pawn, and the other center pawn needs to be defended by pieces for the foreseeable future, and he doesn't have the attacking chances that could be expected from the mainline. Following Black's likely 8. ... a5, White can't even chase away the Black bishop with b4. Despite this, Stockfish rates White at about 0 to +0.5. What resources does he have?

There is also the following similar line, where if I didn't know any better, I'd say White ends up with many of the same problems including a meddlesome knight on his kingside, yet Stockfish rates this as about equal:

[FEN "r1b1k2r/pp3ppp/1qn1p3/2bpP3/6n1/2PB1N2/PP2QPPP/RNB2RK1 b kq - 3 9"]
1. e4 e6 2. d4 d5 3. e5 c5 4. c3 Nc6 5. Nf3 Qb6 6. Bd3 Nh6 7. dxc5 Bxc5 8. O-O Ng4 9. Qe2

I am not too excited about this line for white either. Probably there is a reason that it is not played much.

What resources does he have?

As in most French, white has more space, two good bishops (vs one good for black) and if black castles short there are always ideas with attacking the king because most of black's forces are concentrated on the queen side.

Also, because you took on c5, white does not have to worry anymore about black taking on d4, making it easier to play particularly for a more positional player.

As for future plans, black most likely wants to play a5 to prevent white playing b4, Be3, a3, c4... Black's pieces are currently placed ok, but there is not much they can do from where they are. Likely sooner or later black wants to attack in the center with f6 or even d4.

After black's a5, the square b5 gets weak and white can target it developing for instance with a4, Na3, Nb5, perhaps later putting  a knight on d4.

And if black castles short kingside attacks are always an option.


What are examples of very aggressive openings? One of my favorite openings is the King's Gambit.  It is extremely aggressive, and makes for a sharp tactical game without sacrificing too much material.  It isn't played much at the highest level at standard time controls, but even today it is occasionally used in blitz by top level players such as Hikaru Nakamura.
What other openings for black or white would force these kind of very aggressive, tactical, sharp and open games?  (Without putting yourself in too bad a position.)

The most (overly-)aggressive openings I know of that aren't too bad would probably be the Danish Gambit (Accepted) and the Fried Liver Attack.

Danish Gambit Accepted:
[FEN ""]
1.e4 e5 2.d4 exd4 3.c3 dxc3 4.Bc4 cxb2 5.Bxb2

White gets three open files and both bishops on open diagonals facing black's king; black gets two pawns.  Usually considered slightly better for black, but played occasionally even up to master level.

Fried Liver Attack:
[FEN ""]
1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Ng5 d5 5.exd5 Nxd5 6. Nxf7!? Kxf7 7. Qf3+ Ke6 8. Nc3

White sacrifices a knight to get Black's king out right away.  Proper defense is extremely difficult over the board, but played correctly, black is thought to have a slight advantage.  In most lines, white wins their material back.


How did the engines improve since Deep Blue? Computer chess engines have gotten better since Deep Blue beat Kasparov in 1997.

Did the algorithms get better, or were the improvements mostly due to the same algorithms running faster thanks to faster hardware, etc.?

If the former, are these algorithmic improvements public?

And if so, what were the improvements? Where can I read about them?

Maybe you can take a look at TalkChess, a forum dedicated to computer chess. I found a recent thread that might be interesting for you: Progress in 30 years by four intervals of 7-8 years

A couple of matches between (former) top engines are played on the same hardware. The test suggests that in the recent years (2002-2017), the gain is mainly made by software improvements. In the test, Stockfish (2017) scored an impressive 94/100 against RobboLito (2009), while RobboLito, on its turn, crushed Shredder (2002) with 92/100.

An important remark: as parallel computing is not implemented in the older engines, the test was performed on a single core. As a result, the hardware gain by parallel machines is not measured. On the other hand, you could argue that parallel computing is also a software gain: it is not easy to design and implement an efficient and well-scaling parallelization for the search algorithm.

The Stockfish engine is open source, so the algorithmic improvements are public. A lot of documentation can be found on https://chessprogramming.wikispaces.com


How to recapture more efficiently? I know this sounds ridiculous but I want to learn the hand movement for recapturing in chess. It seems like a good fast way to recapture especially in blitz. Here is an example if you don't know what I'm talking about (the way they quickly recapture/capture a piece).

https://www.youtube.com/watch?v=c9NG8J2yow4

Practice makes perfect. I've seen several different ways on how to capture pieces. It's not really something that you learn, but more like something that goes automatically. So, just try it a few times at home (without thinking, so it goes automatically), and do what feels the most natural.


What's the difference between a USCF 1600 and 1700 What aspects are 1700 generally stronger than 1600 chess player?s

I'm a 1600 chess player. I can defeat 1600 chess players, but I lose to 1700. I was wondering what makes a 1700 stronger than a 1600? What can I do as a 1600 to start winning against 1700 chess players?

This is difficult to answer. They are generally stronger in some or all of the following areas:

Tactics
Endgames
Planning
Recognition of positional features
Openings

However, they may be weaker in some of those areas than a 1600. My point is that there is no well-defined set of knowledge that makes someone a 1700-level player. They have just enough of a hodge-podge of experience and maybe some studying that they can stumble into wins against those with less experience. In fact, when you get to 1700 from 1600, you probably won't feel a tangible difference in the way you think about the game or make moves. Your results will simply be just a little better.

As for how to win against them: play better chess than they do. Study the things that I mentioned above (although I would avoid openings). One piece of advice that I've heard before for generating upsets is to make the game as complicated as possible, to maximize the likelihood that your opponent misses something major.


Was this “caterpillar” strategy a good way to advance my pawns? I recently played an endgame as Black in which I thought up a silly, but effective, to advance my doubled pawns. Here is the relevant part of the game.
[FEN "8/6p1/2p2kp1/1p1p4/p2P2K1/P1P5/1P6/8 w - - 0 1"]

1. Kf4 g5+ 2. Kg4 g6 3. Kg3 Kf5 4. Kf3 g4+ 5. Kg3 g5 6. Kg2 Kf4 7. Kf2 g3+ 8. Kg2 g4

Then White ran out of time and I won.
We were both down to the seconds on the clock, and I thought that this was a good idea. That was because I thought, “Why must I think, when I can just herd the White king down the board is a systematic manner that saves me from wasting too much time on future thought?”
However, was my “caterpillar” plan really a good strategy in this endgame situation?

tl;dr: "Yes."

Discussion:
Technically, this position is governed by the basic concept of the "Outside Passed Pawn" and the winning method is to use that pawn to restrict the opposing king's ability to defend the other pawns on the board.

The purest expression of that concept is in David's answer, which is to just use the one pawn and leave the other as a Damoclean Sword dangling over the head of your opponent's king.

But, given the special case of this situation (you actually have two outside passed pawns, not just one) you could also decide play it strictly as a single g-pawn endgame, but with tempo move in hand. To do this, you would use the caterpillar's "head" (the lead g-pawn) along with your king to drive the opposing king backwards to the back rank. (While doing this, when your king moves beside your pawn, keep it to the center -- f file -- side of your g-pawn.) When that is accomplished (let's say your K reaches f3, the pawn g3 and your opponent's K goes to f1 to prevent your king from advancing in front of the pawn) you simply push the g-pawn forward to g2 and when he moves to g1 to block the advance of the pawn, then you move the rearmost g-pawn from g7 to g6, leaving your opponent the choice of getting out of the way of your lead g-pawn and letting it queen, or moving one of his other pawns and letting you create a queen from one of your other pawns.

I would probably have played it that way, simply because it seems the least complicated to me, but there are multiple winning ideas in this position, and none of them are objectively better than any other.


In this QGD Exchange variation, how should white deal with 6 ...Bg4? [FEN ""]
1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.cxd5 exd5 5.Bg5 Be7 6.e3 Bg4!?

The Shredder Opening Database indicates no games played with this move, and my edition of John Watson's A Strategic Chess Opening Repertoire does not cover it either (unless I'm missing a transposition of some sort), so you would expect this move to be somewhat dubious.

Yet, according to my analysis with Stockfish, not only is this move OK for Black, but White struggles to maintain an advantage without either giving up his white squared bishop or allowing Black to get his white squared bishop into the game without concessions (both important themes in this opening for White, as I understand it).

What are the main ideas for White in this line? Can White punish Black for this bold early move?

Here are a few variations that I looked at with Stockfish - I focused on what I consider "natural" moves rather than radical ideas. Is there a line I'm missing that spoils this idea for Black?

[FEN ""]

1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. cxd5 exd5 5. Bg5 Be7 6. e3 Bg4
7. Nf3
( 7. Qb3 Nbd7 8. Bd3 ( 8. Bf4 O-O 9. Bd3 Nb6 10. Nge2 c6 11. O-O
{ Eval: 0.15. Black's white squared bishop is developed and he seems to
have solved most of his problems.}  )
8... c5 9. Bxf6 Nxf6 10. dxc5 O-O 11. Nge2 Bxc5 12. O-O d4
13. exd4 Bb6 14. Rac1 Rc8 15. h3 Be6
{ Eval: 0.29. A pawn down, but White's isolani seems like it would
be easy to recapture.}  )
( 7. Nge2 O-O ( 7... Nbd7 8. h3 Bf5 9. Ng3 Bg6 10. Bd3 Bxd3
11. Qxd3 { Eval: 0.25. Exchanging white squared bishops must
be a small concession from White.}  )
8. h3 Bxe2 9. Bxe2 Nbd7 10. O-O
{ Eval: 0.25. This seems like the most promising line for
White if you want a quiet position,
but Black seems reasonably well developed.}  )
7... c6 ( 7... O-O 8. Bd3 c6 9. O-O h6
{ Eval: 0.19. The Black white squared bishop is
nicely developed, and the king is safe.}  )
8. Bd3 O-O 9. Qb3 ( 9. Qc2 h6 10. h3 Bxf3 11. Bxf6 Bxf6 12. gxf3
{ Eval: 0.16. White has kingside attacking chances at the cost of a
messed up pawn structure and dubious king safety.}  )
( 9. h3 Bh5 10. Qb3 Bxf3 11. gxf3 Qc8 12. Rg1 { Eval: 0.37:
White attack on kingside looming, but with messed up pawn structure
and king safety issues.}  )
9... Bxf3 10. gxf3 { Eval: 0.34. This position seems double
edged - the White rook going to g1 looks dangerous, but the pawn
structure is messed up and I'm not sure about the White king's safety.}

Usually white's aim in this line is to play Qc2 anyway to take away the F5 square from the black bishop. Therefore I dont think Nf3 is a great move. Its better for white to play Qc2 or Qb3 which is also thematic since blacks white squares on the queenside are now weak due to absence of the bishop.


Why don't the ratings of Carlsen and Caruana change after 4 games in the WCC 2018? By now there were 4 games and all were drawn. Should it not mean that Caruana should get points?

The exact workings of FIDE rating calculations can be found in the official rules. As you can see in Table 8.1b, a rating difference of 3 points (as is the case with Carlsen-Caruana) means that both players have the same expected score: 0.5. The value of ΔR, which is the expected score minus the result (in the case of a draw, 0.5) is therefore 0.5-0.5=0, i.e. no change in rating.

If instead their difference were 4 points rather than 3 (meaning that Carlsen's expected score would be 0.51 instead of 0.5), a draw would mean that his ΔR would be -0.01. With a K value of 10 (as he has a rating above 2400), his gain/loss would therefore be -0.01*10. In other words, a draw with a rating difference of 4 would mean that he would lose 0.1 rating point (whereas Caruana would gain 0.1 point).


An aggressive opening for Black against 1. e4 I am a novice at chess. I am around 1400-1600 chess rating. I have struggled to find any sound aggressive openings for black against E4. As white I play the Scotch Gambit which I have great success with.

Can anyone recommend any sound openings for black that are aggressive and could you explain the theory behind it also? I prefer openings that don't need a lot of lines to remember.

White is one move ahead, and attacking. You can't be aggressive yet, or you'll just lose!

You have two choices: either you try to contain white, and when that is done and the position is equal, then you try to become active yourself. Or, you let him expand, but make sure you'll have your own trumps as well. The first way will lead to more or less symmetric positions, the second way is only possible if you make the position as asymmetric as possible: then he can have his trumps, and you can have yours.

The most famous asymmetric way of playing against 1.e4 is the Sicilian.

[FEN "rnbqkbnr/pp2pppp/3p4/8/3NP3/8/PPP2PPP/RNBQKB1R b KQkq - 0 4"]

Example Sicilian after 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4.

If white goes for this (he has plenty other options that are very strong too, black has other 2nd moves with the same idea), then he played 3.d4 to open the center, he'll have extra space, open diagonals for his bishops and great chances of an attack -- but you'll have your trumps too. You have 2 pawns vs 1 in the center, can move a rook to the c-file, and you have no weaknesses. You're very far away from having your own attack, but if white expands too much... BOOM. Not easy to play, but white has no way to simply control the game from here, he needs to attack.

Another way is the Pirc / Modern, characterized by putting a bishop on g7. With Nf6 in it's a Pirc, without it's a Modern. E.g.,

[FEN "rnbqk2r/ppp1ppbp/3p1np1/8/3PPP2/2N2N2/PPP3PP/R1BQKB1R b KQkq - 2 5"]

Again a very asymmetric position, white and black are doing very different things. But white has much more space, and he's looking for an attack. Black is thinking that he will be able to defend, and then, white will have thrown too many pawns ahead, leaving behind all kind of empty space... again, counter attack coming up, if black survives.

So those are ways to play for the counter attack; counter attack is only possible if you manage to weather the attack first.

Otherwise, forget about attacking for now, and try to get an equal position.


How can I use stockfish to find good moves, instead of just bad moves? After playing on lichess.org I have been reviewing my games as follows:

Ask for a computer evaluation (Stockfish)
Look at the graph and investigate any wild swings in computer analysis
Try to understand why a particular move was a blunder

While this seems to work, it's a very negative approach as it doesn't seem to find any good moves that I've made.  For example, at my level (Blitz ~1230) I might win a game because I laid a trap which my opponent failed to see.  Stockfish of course sees through the trap and the evaluation shows I made a suboptimal move even though against this particular opponent it resulted in me winning a piece.

Is there any way to find good moves that I made, rather than just non-mistakes?

Sorry, computer engines are not designed to think like a human. It's a machine, it's written to play strong chess. There is no intelligence in there to think like that.

The "good moves" you mentioned were actually bad moves at Stockfish's level.


Opening a chess club Beside the chess sets and clocks, what materials are needed? I took care of the place, I'm talking about chess materials needed.

Now lets talk about the materials, I would like to buy them this week, I was looking at wholesalechess.com, but I wanted to ask you first, you are the almighty experts.

What I want is to buy,  between 10 or 12 chess sets and 10 or 12 clocks (Do I need something else?)

I want free shipping to Lebanon, middle east, I want something that is quality and somehow cheap, I would prefer digital clocks, and club chess sets like this

I would like to be able to communicate with the seller, maybe I could ask him for a discount, or ask him for advice. I would like buyer protection, credit card gateway (paypal isn't available in my country) new items, nothing used, fast support, and fast shipping (ideally less than a month).

Second question here.

The manufacturer of the Game Timer II clock used to give a good discount to anyone buying 5+, but that was before they were owned by Excalibur; no idea if they currently do.

In my experience running a chess foundation, most of the manufacturers are open to quantity discounts, but you need to contact them directly in order to find out what they are. (Often they will give you the same price they give the retailers.) Retailers like wholesalechess.com are often willing to do some discounting, but usually they give you a table on their website of where the quantity breaks come in. Sometimes the price breaks don't happen before 25 or 50, though.

Bottom line is it never hurts to ask.

As for what else, depends on what you're aiming for with the club. Boards, sets and clocks are all you really need to get going. Other supplies might include pencils and scoresheets for official games, a large demo board (or electronic display, depending upon budget -- we typically use demo boards with pockets on each square for the piece) can come in handy if someone is going to give demonstrations or lessons for the club members.


Can White get a theoretical advantage against the Sveshnikov Sicilian in today's theory? I'm looking for an opening expert or an experienced Sveshnikov player that knows the answer to this.

The Sveshnikov has been increasingly popular and it has also proven to be very good for draws. However, is there a line that like grants an unclear line that will give White a chance to fight for an advantage?

Also which line is considered better for avoiding a draw, the Bxf6 first line or the Nd5 line?

Let me answer your second question first: According to chesstempo db there are 6% less draws after 9.Bxf6 than after 9.Nd5, with White and Black each getting 3% more wins!
As far as a theoretical advantage: hoacin's comment is accurate.  Of course like all openings it is more about heading to the positions you like or are more comfortable with; thus many GMs would say that 3.Bb5 is the best move against the Sveshnikov.


Alternative approaches to chess engine programming As far as I understand, roughly speaking, chess engines work by:

calculating all possible variations (game tree) up to some depth
evaluating the final position based on some criteria (material, piece activity...)
based on this evaluation decide for the best move

I fully understand that to have an efficient engine there are ways to prune certain lines, limiting the depth, etc; but this is not my question.

Question is: Are there any alternative attempts to program a (not necessarily strong, but not random either) chess engine, which does not follow this scheme?

In the beginning years of computer chess, people have actually tried to teach computers chess in the same way as they do with humans, explaining strategic concepts like a healthy pawn structure or the initiative. These attempt were soon abandoned because the method you describe was much more successful.

Recently, there has been another attempt to let an engine teach itself chess via Deep Learning (probably encouraged by the success of Google's Go AI). According to the article I linked to, they were quite successful and managed to reach IM strength.


Different number of day options in tournaments I'm thinking of entering a chess tournament, and finding it very hard to decode some of the jargon in the tournament listings. The tournament I'm considering entering has 4-day, 3-day, and 2-day options, and I can't figure out how this works regarding the possibility of winning 1st place in your section. Can someone give a general run-down of what the consequences are of joining the 2-day option vs the 3- or 4-day? Can you still win the tournament? How could that work, given that you cannot possibly play some of the other people in your same section but who chose the 3- or 4-day option, since the time controls are listed as being different?

It's my understanding that all of the players, regardless of whether they started in the 2, 3 or 4-day options, merge on the final day of play. Playing fewer days means you will play faster time controls in the early rounds, so that everyone plays the same number of games, up to the final day's rounds, which are played at the slower time control. The winner is determined like in any other Swiss, by who has the most points at the end of the tournament.


Why did Black resign this game? This is a game between Jose Raul Capablanca and Viacheslav Ragozin, Moscow 1935:

[FEN ""]

1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.a3 Bxc3+ 5.bxc3 d6 6.Qc2 O-O 7.e4 e5 8.Bd3 c5 9.Ne2 Nc6 10.d5 Ne7? 11.f3 Nd7 12.h4! Nb6 13.g4 f6? 14.Ng3 Kf7 15.g5! Ng8 16.f4! Ke8 17.f5 Qe7 18.Qg2 Kd8 19.Nh5 Kc7 20.gxf6 gxf6 21.Ng7 Bd7 22.h5 Rac8 23.h6 Kb8 24.Rg1 Rf7 25.Rb1 Qf8 26.Be2! Ka8 27.Bh5 Re7 28.Qa2 Qd8 29.Bd2 Na4 30.Qb3 Nb6 31.a4! Rb8 32.a5 Nc8 33.Qa2 Qf8 34.Be3 b6 35.a6 Qd8 36.Kd2 Qf8 37.Rb2 Qd8 38.Qb1 b5 39.cxb5 Nb6 40.Qa2 c4 41.Qa3 Qc7 42.Kc1 Rf8 43.Rbg2 Qb8 44.Qb4 Rd8 45.Rg3 Rf8 46.Ne6! Bxe6 47.dxe6 Rc7 48.Qxd6 Ne7 49.Rd1  1-0

I understand that Black is in a bad spot, being two pawns down and almost the epitome of cramped (not to mention the promotion possibilities for White), but the game doesn't look obviously lost to me yet.  My suggestion would be 49... Nbc8 forcing the White queen back and then 50... Rg8 countering the sting of White's g-rook.  I've played several variations from this point and all of them end up with White keeping the two-pawn advantage, but not a quick win.  Am I missing a certain move by White to refute anything Black could do here?  How did Ragozin know that there was no chance of a draw?

Edit: It has been shown that after 49... Nbc8 50. Qd2 Rg8? 51. Rxg8 Nxg8 White wins at least the Black queen with 52. Qd5+.  However, if White plays 50. Qd2, Black has 50... Qxb5 winning a Pawn and considerably uncramping himself (or so it seems to me):

[FEN "k1n2r2/p1r1n2p/P3Pp1P/1q2pP1B/2p1P3/2P1B3/3Q4/2KR2R1 w - - 0 50"]

Black is down 2 pawns, pieces completely passive, the pawn on e6 is impossible to get rid of, pawn on h6 is also important, creating potential outpost on g7 for rook. White also has two bishops and controls both open files. There is no need for White to prove anything by concrete analysis. Unless Black has some immediate way to get material back - he might as well resign and save energy for next round.


Why is f4 considered as bad in the opening? I really like to play openings that contain f4 (f5 as black) for a number of reasons.

It cannot be challenged with d pawn, which is initially protected by the queen.
When the king knight is developed, the f pawn is no longer blocked.
Unlike c pawn, it can be easily supported by castling kingside up to the board, and helps the development of the rook if exchanged.
After king's pishop fianchetto, the diagonal is open and the bishop is very strong there.
Even if exchanged early, after castling kingside, the king rook has a semi-open file, which makes it stronger.
Enables Ng5 move, which can be nasty sometimes.

But usually this move is considered bad, or dubious at the best by grandmasters and engines. What is the reason?

      [FEN ""]
      [StartPly "3"]

      1. e4 e5 2. d4 exd4 3. f4 Nc6 4. Nf3 Bc5 5. Bd3 Nf6 6. e5 Nd5 7. O-O O-O 8.
Kh1

      [FEN ""]
      [StartPly "3"]

      1. e4 e5 2. d4 d6 3. f4 exf4 4. Bxf4 Nf6 5. Nc3 Nc6 6. Nf3 Bg4 7. Be2

It is not really possible to answer this generally as chess is more complicated and it really depends on what black is playing whether an early f4 is good or not.

I guess, what you actually like is the combination of e4 and f4. There are many examples where f4 is perfectly playable, such as in some Sicilians, the French defence and other semi-open games.

In open games (1. e4 e5) playing an early f4 tends to be somewhat dubious at the highest level, but is of course perfectly playable at the club level.

If you want a system opening with f4, why don't you play the King's Indian Attack, where "f4" is often ok whatever black does?


Best practical chances after g5 forking knight and bishop I am a beginner playing white and it's my turn to move. What is the best possible move in response to this fork?

 [title "Game position after fork:"]
 [fen "r1bqr1k1/ppp2p2/2n1pn1p/3p2p1/1b1P1N1B/2N1P3/PPPQBPPP/R3K2R w KQ - 0 1"]

Disclaimer :  in any case you are lost if your opponent plays reasonnably enough.

Assuming that you don't want to resign at move 10, my suggestion would be to continue with 10.Bg3 gf4 11.Bf4. Black's king is slightly weakened, you hit h6 and plan to continue with 0-0-0,f3,g4,h4,g5 to try and open his kingside as much as possible. In positions with opposite castles, material is not the single most important criteria, king security and initiative matter too.

If Black plays passively or conservatively, say 11...Kg7, then 12.f3 prevents Ne4, and with Bd3 and g4-g5 you may be able to muddy waters enough to induce later mistakes by Black.

If he plays actively and purposefully, with 11...Ne4 (or even 10...Ne4) 12.Qd3 e5!, not worrying about the Ph6 and intending ...Bf5, well, you hardly have anything to hope for...


Chess Statistics How to? I am a graduate student studying statistics and I play chess once in a while for fun.

I was thinking (just for the fun of it) -- applying some of what I've learned in statistics to chess games: I want to perform statistical analysis of chess games.

Note: My primary purpose is recreation:

Tinkering around
Re-producing earlier works -- for example how much of an advantage does white have over black
Looking at mid-game winning patterns
Etc. etc.

So to that:

I need a large collection of chess games (historic data)
I will then analyze them using R which is a statistical programming language

Question:

I'm looking a collection of games that I can then use as my data set (I would love to get a list of open source chess databases -- commercial chess database might have restrictions on em)
I'm looking for any reference material -- like seminal papers in this area.

Thanks.

I'll leave others to point you a correct database for the games because I'll focus more on the statistical part.

First, you need to ask yourself what you want to analyze. If you don't know, you should really ask yourself what problem you want to address. Your question simply say "I want to do something, but I don't know what to do.". There're infinite ways how a database of chess games can be analyzed. I'll point to you for some areas.

Whether white has an advantage

Given a large data set, if we assume the games are independent we might strip away the draws. Then we might assume a binomial distribution with p=0.5 and try to detect statistical significance. However, this approach assumes that the players are equal.

There's rumor that Carlsen got most of his points from players older than him (last generation like Anand) but suffers against like Caruana and Giri. Is that true?

You might use a two samples-mean t-test or something like that.

Whether Elo rating is really inflated
Given a set of games between two players (or computers), is one player really better than another?

For example, Carlsen has beaten Nakamura many games without a loss. Does it mean Carlsen is a better player? Did that happen because Carlsen was simply lucky.

Correlation between world-number one and world champion

Is there a positive correlation? Are they independent?

Whether the Elo rating system really make sense

There were some articles on Chessbase about it a while ago. I don't remember the names so you'll need google yourself.


Can a piece pinned to my king put the opponent's king in check? I was playing a game with a friend online. A situation came up where he put me in check with his bishop, and I moved my rook to block it. His king was on the g file and my rook was on g2. The website said he was in check.

[fen "6k1/8/2b5/8/8/8/6R1/7K b - - 0 1"]

Position after Rg2+ , showing only the pieces important to the question.

I didn't think it could be a check, since legally, I could not attack his king or move my rook because it would put my king in check. Can a piece put a king in check even though moving that piece would be an illegal move?

This is odd, because since he was forced to respond to the check, I was able to make a couple moves and leave him with only a couple of blocked pawns, while I was able to promote a pawn and mate in a couple moves. I won, but it feels like cheating. He had a better position and should have won.

Yes. Besides making sense, it's also explicitly stated in the rules of the game:

3.9
The king is said to be 'in check' if it is attacked by one or more of the opponent's pieces, even if such pieces are constrained from moving to that square because they would then leave or place their own king in check. No piece can be moved that will either expose the king of the same colour to check or leave that king in check.

Source: Laws of Chess on the FIDE site


Why is White's "25. Bh4" considered a great move in Karjakin vs Kramnik at FIDE Candidates Tournament 2018? I was watching Karjakin vs Kramnik at the FIDE Candidates Tournament 2018, Round 9, and simultaneously observing the chat feed at chess24.com, where people unanimously glorified the move 25. Bh4. Why was it considered such a good move?

[FEN ""]
[Event "FIDE Candidates Tournament 2018"]
[Date "2018.03.20"]
[Result "1-0"]
[White "Sergey Karjakin"]
[Black "Vladimir Kramnik"]
[StartPly "49"]

1. c4 e6 2. Nc3 d5 3. d4 Nf6 4. cxd5 Nxd5 5. e4 Nxc3 6. bxc3
c5 7. Rb1 Be7 8. Nf3 O-O 9. h4 cxd4 10. cxd4 Nc6 11. h5 f5
12. exf5 Qa5+ 13. Bd2 Qxf5 14. Bc3 h6 15. Bd3 Qg4 16. Kf1 e5
17. d5 e4 18. dxc6 exf3 19. gxf3 Rxf3 20. Be2 Rxf2+ 21. Kxf2
Bc5+ 22. Kf1 Qf4+ 23. Bf3 bxc6 24. Be1 Be6 25. Bh4 Rf8 26. Kg2
Kh8 27. Rc1 Rf5 28. Rc3 Rd5 29. Bxd5 Bxd5+ 30. Rf3 Qg4+
31. Bg3 Bd6 32. Rh3 Be7 33. Qe2 Be4 34. Qf2 a5 35. a4 c5
36. Rh1 Bf6 37. Re1 Bc6 38. Ree3 c4 39. Qe2 Qxh5 40. Qxc4 Bd7
41. Rd3 1-0

The reason behind 25. Bh4 is very concrete, namely: With Rf8 coming next for black, white's bound to play Kg2 to unpin and cover f3 but without preparing it with Bh4 it leads to the following forcing variation:

 [title "25. Kg2 without Bh4"]
 [fen "r5k1/p5p1/2p1b2p/2b4P/5q2/5B2/P7/1R1QBK1R w - - 0 1"]

 1. Kg2 Qg5+ 2. Bg3 Rd8 3. Qxd8+ Qxd8 4. Rb8 Bc8 5. Bg4 Qd5+ 6. Kh2 Bd6 7.Rxc8+ Kh7

This line forces white to give up the queen for the two pieces, and it is definitely still among the winning variations for white but for practical reasons I reckon Karjakin intended to keep his queen on the board and avoid that variation for good, which he perfectly achieves with 25. Bh4 as it stops both Qg5+ and Rd8 and sets up Kg2.


In a online game, is it considered good etiquette to offer a draw when the opponent obviously misclicked? For example, instead of capturing (and therefore exchanging) the queen on d8, white moved his queen from d1 to d7, and black can capture this queen for free. This is very likely the result of a misclick by white. Another example is moving the king for no reason in the opening stage. In this case, is it considered good etiquette for black to offer the draw, instead of taking advantage of white's misclick?

Some possible exceptions:

My position is already winning before my opponent's misclick.
My position is still losing even after my opponent's misclick.
My opponent made a blunder which does not seem to be a  misclick.
My opponent demonstrated bad sportsmanship before misclicking.

In all above four cases, I will not offer draw.

Just to offer a different answer:

No. No takebacks, no draw offers. In short time controls this is part of the game. It's the same as a blunder under pressure. I pressured the opponent on either time or position, and the person cracked and made a mistake.

Or your other example, of moving the king instead of castling in the beginning: That's what one get for trying to blitz out moves. Might save you a second here and there, but the risk is these mis-clicks. That's a price my opponent will have to pay, can't have the cake and eat it too.

(For longer time controls (1h+) I might think trying to salvage the game is the right choice, but I only really play 5min and below)


Why is black playing ...f6 to attack the e5 pawn a bad move in the King's Indian Attack? I have been studying the King's Indian Attack a bit recently, and have started reading through Neil McDonald's Move by Move book on it.
Earlier today I played a game against a 2100 on Lichess (I am around 1700 rapid) and attempted to play the KIA against my opponent's e3 Sicilian. After the first few moves I pushed my e4 pawn to e5 like the McDonald book talks about and then my opponent played 10..f6, leaving no way for me to keep my pawn. I thought that if this were viable I must have messed up the move order and quickly resigned after losing my only central pawn. Checking it with the engine, it looks like a slight inaccuracy from my opponent, going from about a -0.5 evaluation to 0.5 in my favour. But why is this? How am I supposed to "punish" this decision?
[Event "Rated Rapid game"]
[FEN ""]
[Date "2021.04.13"]
[Result "0-1"]
[UTCDate "2021.04.13"]
[UTCTime "04:29:14"]
[WhiteRatingDiff "-2"]
[BlackRatingDiff "+1"]
[Variant "Standard"]
[TimeControl "300+8"]
[ECO "B40"]
[Opening "Sicilian Defense: French Variation"]
[Termination "Normal"]

1. e4 c5 2. Nf3 e6 3. d3 d5 4. Nbd2 Nc6 5. g3 Nf6 6. Bg2 Be7 7. O-O O-O 8. e5 Nd7 9. Re1 Qc7 10. Qe2 f6 11. exf6 Nxf6 0-1

I looked in the database for similar games but at least in the masters' database I'm having difficulty finding the common theme in white's winning plan. From what I have seen, I'm thinking black's e6 pawn becomes a target now that it's sad and alone, and maybe if a c4 pawn break was built up, the c4-f7 diagonal to the king is dangerous? Would anyone with a better understanding of chess be able to tell me if this is correct or if there might be anything else wrong with ..f6?

You are right that e6 is your target and also that a winning plan is not trivial to find, that is because there is no clear win. The weak square e5 and the weak pawn e6 often do not guarantee a win, but usually white has a long-lasting slight advantage.
f7-f6 attacks a pawn chain (ok, this is not really a pawn chain, but it would be, if your pawns were on c3 and d4) from the front (the e5 pawn). c7-c5 (or b7-b5-b4) attacks it at the base (the d4 pawn, which is not on d4 in this example). c7-c5 is less weakening than f7-f6, because d4xc5 does not weaken the d5 pawn, but e5xf6 weakens the e6 pawn. Still, f7-f6 is often ok (this view has changed during chess history), when black gets dynamic counterplay. We see these ideas often in the French defense. Sometimes black manages to play e6-e5, completely freeing his game, though the then slightly weak d5 pawn is something black has to take care of.
So in this game you should have played calmly for control of the e5 stop square (see Kmoch:"Pawn Power in Chess", diagram 75), bring your bishop to h3, your knights to f3 and e5, and triple your heavy pieces on the e-file.
Once all your pieces are placed well, and his are bound to the e6 pawn, open a second front, for example with a2-a3 and b2-b4 or with c3-c4, or by pushing your pawns on the king side. This is according to Dworetzkys "Theory of the two weaknesses", which says that one weakness (e6 in this case) can be defended, but two or more weaknesses often can not.
Edit: And what you obviously should not do is resigning just because you have no idea what to do. In such a case, check out which of your pieces are not well-placed, and improve their position (Rowson: "Talk with your pieces"). For example, I would have played 12.Ng5! and on 12... e5 13.c4!, and if he plays 13...d4 then I have a beautiful square e4 for the knights. Looks won for white, at least in a human vs. human game. For example, the bishop c1 (and therefore Ra1) are bad pieces here, so play (the slightly unusual) 12.b3! in order to control d4 and e5 with the bishop b2.


Is there modern chess software similar to ChessMaster series? I'm interested in a software for a middle-casual player.

It should have learning tools, rich graphics with modern screens support and some entertainment features, similar to ChessMaster. Chessmaster is good but seems to be outdated.

Applications like Fritz are too heavy and UI has always been a second class citizen for them.

You should have a look at LucasChess . It has a lot of interesting learning tools (i.e. Play like a Grandmaster) ,  40 (!!!) engines from 0 to 3300 ELO and a really nice UI. It is free and is actively developed.


Would it be a decisive advantage, if the opponent would not be allowed to castle? Suppose, you play a normal chess game, with the only exception that the opponent
 is not allowed to castle, but you are.

Do you have a decisive advantage ?

In fact, Larry Kaufman (Komodo) did computer testing on this with Komodo, and found that White has about 50% winning chances when Black starts with no castling privileges. So it's a toss-up.

http://talkchess.com/forum/viewtopic.php?p=650339#650339

  Here is a perfect example: In the initial position, forbid Black from
  castling. Komodo gives that position a score that is around where I
  think the dividing line between win and draw lies. I had Komodo 9.3
  play it out on four threads (to insure variety due to MP
  unpredictability) a hundred times at game in one minute. getting 49
  White wins, 46 draws, 5 Black wins. Then at two minutes plus one
  second, a similar result: 49 White wins, 49 draws, 2 Black wins. So
  just forbidding castling for Black appears to put the game right on
  the win/draw line. Of course results could be different at TCEC time
  controls on many cores, but it's not obvious whether the White win
  percentage would go up or down.

There have been some who have dubbed this "Kaufman chess", and suggested it as a sort of long-time control Armageddon method (rather than two rapid games, then two faster games, then two blitz games, and finally a blitz Armageddon, as in the FIDE World Cup).


What are some methods that tournaments use to limit draws? There has been a rising faction of chess players who believe that professional chess is too drawish. What are some ways that tournaments fight against the prevalence of draws?

The problem with chess having a large number of draws cannot itself be solved - it is simply a result of the defensive possibilities in many systems and the fact that high-level play reduces the number of losses due to simple mistakes. Without a fundamental change to the rules of chess this is not likely to change.

There have been several measures to prevent top players from agreeing to draws before the positions are completely played out, which I'll mention below. One thing to keep in mind, however, is that draws by agreement are often used by players in long tournaments as a way of preventing fatigue or simply playing on in dead positions until someone makes a mistake, and it's up for debate whether forcing/encouraging play in such conditions makes for chess that is more interesting or of better quality, or if it detracts from the events in which those rules are used.

The most commonly talked about variant is what are known as 'Sofia rules' (introduced in a tournament at Sofia in 2005), which states that no draws can be agreed before the position itself becomes a theoretical draw, though this assumes that the arbiter is theoretically competent enough to realise that the drawn position is a draw, and doesn't stop the players deliberately trading down into such a position.

The main other option that has been suggested is to provide more points for a win than for a draw, thereby hopefully making the players want to push for a win as a win and a loss is still worth more points than two wins. There has been some discussion that this is unfair to players in hard-fought draws, however.

I'll also link you to this wikipedia article, which lists some other things that have been suggested over the years.


Worrying inconsistency in playing strength I recently found time to make a study plan and improve my playing strength. Using this plan, I was able to achieve a 1900 average rating on online chess sites.

Since a couple of days, I have in a certain sense "lost the feel" of the game, for seemingly no reason at all, and my playing strength quickly dropped to the 1600-1700 range. No matter how hard I try, I don't seem to regain those abilities I had mere weeks ago.

How do I get that "chess focus" back? Has anyone had this experience before?

Don't worry you're not alone in this, I can assure you almost all chess players/enthusiasts go through such periods, not only at the start, but throughout their whole chess experience. Of course there are many elements involved here, that at the end of the day define your performance, but let's stick to those that are most common for all: (bear in mind these points are purely speculative as I cannot possibly know what may be truly causing your performance drop without actually knowing you!)

Learning curve: Basically whatever new we learn and try to incorporate with our chess knowledge, be it new tactics, new positional ideas, more opening varieties, weird endgame situations, etc. there's some minimum necessary time involved (different for everyone of course) to be able to put these new ideas into practical usecases and actually make them work. Why? well one immediate reason is that everyhting in chess requires some amount of experience until it comes closer to being understood. Prime example is when we all first learnt about different checkmating ideas, and then wanted to immediately apply them in every game we played, and of course instead we just end up losing because by giving such strong importance just to some checkmating pattern we become completely ignorant to the more basic ideas underlying each position (activity, safety, structure etc.). So I think you most probably had an immediate boost to your rating (reaching 1900) more by blind chance than anything else.
What you should retain from my first bullet point is: stay positive (i.e. care more about your play than rating, it's just a number after all...) and keep playing your usual chess, and whatever new you learn along the way, as you keep playing you will get more and more appropriate chances to putting them into good use, meaning you should let the occasions present themselves first and then try applying what you've learnt. By no means you should take this statement as equivalent to "not controlling the evolution of the game", after all that's the whole point of positional play(keeping a grip on the position and imposing its evolution on your opponent to the extent that you can), my point only concerned specific precise new things that you may learn, e.g. rook endings, or known theoretical drawn configurations etc. In this way you will slow by slow incorporate everything new that you learn much more naturally. Simply put by playing more you will discover more about the applicability of the things you've learnt.
Now one orthogonal reason to the previous two would be: ratings are always fluctuating, specially on online servers (we most often just play for fun and mess around hence may end up losing a lot of points suddenly-also bearing in mind that they're usually short time control games->hard to keep a consistent rating), so I think everyone experiences this at any level, what is more important is your average rating, say in the last 2 months, that says a lot more about your performance. I myself have always had drops of roughly -+200 rating points every now and then, same goes for most of my friends and people I play against. Chess is really a lot about struggling, because of the extremely rich dynamics of the game, in every game there are so many things that are completely different and unknown compared to our previous experience.
Another point you brought up was "chess focus": One's mind may very well be completely at ease before sitting down and playing a game of chess, but may still lose his/her focus easily during the game if not careful. At any stage of the game, it is extremely crucial to stay completely alert of at least the most important elements of the position (no need for examples here really). But how? well apart from the fact that everyone has different ways of getting hooked into a game (concentrating), there are general ways of staying focused: e.g. whether it's your turn to play or not, you should be continuously calculating relevant lines to your postions, and absolutely avoid saying to yourself "I'll just wait and see what he/she plays then I'll think about my move", instead you should always assume that there are more things to the position at hand that you see at first sight, so the more you try to calculate different variations (within the time you have) regardless of whether they're working lines, you will nonetheless discover more about the space of possibilities hidden in the position, and always assume your opponent is going to play the best move you can think of. All of this, as part of your general attitude towards chess-playing, will to some extent improve your focusing abilities.
Enough with speculations :) My last advice: just keep up your playing routines and don't allow for big gaps of inactivity in your playing as much as you can, don't be ignorant towards your losses, instead dig into them as much as you can and you'll have a lot more concrete improvements resulting from that than anything else. Hope this has been helpful!