Why is 15.cxd6 better than 15.cxb6 here? In Radjabov vs. Gelfand (2013):

[FEN ""]
1.Nf3 c5 2.c4 Nc6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 e6 6.g3 Qb6 7.Nb3 Ne5 8.e4 Bb4 9.Qe2 d6 10.f4 Nc6 11.Be3 Bxc3+ 12.bxc3 Qc7 13.Bg2 e5 14.c5 b6 15.cxd6 Qxd6 16.O-O O-O 17.f5 Rd8 18.Rfd1 Qa3 19.Rxd8+ Nxd8 20.Bg5 Ba6 21.Qd2 Qe7 22.Rd1 Nb7 23.Bf3 Rd8 24.Qc1 Rxd1+ 25.Bxd1 Nd6 26.Bxf6 gxf6 27.Qe3 Qc7 28.a4 Qd7 29.a5 Nxe4 30.Bc2 Qb5 31.Qf3 Ng5 32.Qg2 bxa5 0-1

On move 15, White plays 15.cxd6 instead of 15.cxb6. Why? I can see two reasons to prefer the latter:

It preserves a weak pawn on d6 (and by extension a weak square on d5).
It makes a new isolated pawn on b6 that's on a semi-open file too.

It seems to me that the obvious plan is 15.cxb6 intending O-O, Rfd1 and Rab1, etc. However, Radjabov didn't play this, and Stockfish doesn't like it either; at depth 24 it says 15.cxd6 is 0.00, but 15.cxb6 is -0.80. What's wrong with taking on b6?

There are a few ways White is at a disadvantage here that I found:

Black’s dominance in the center.
The active black knights.
White is left with 3 pawn islands, which is never considered good.

Look at White’s pieces here-no really good moves are available. The knight can't move up and come into play. The rooks are undeveloped/have no open files to dominate. The bishops don't have room to move freely, and the same goes for the queen.

    [Event "?"]
    [Site "?"]
    [Date "?"]
    [Round "?"]
    [White "?"]
    [Black "?"]
    [Result "?"]

    [FEN ""]
        1.Nf3 c5 2.c4 Nc6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 e6 6.g3 Qb6 7.Nb3 Ne5 8.e4 Bb4 9.Qe2 d6 10.f4 Nc6 11.Be3 Bxc3+ 12.bxc3 Qc7 13.Bg2 e5 14.c5 b6 15. cxb6 axb6 16. O-O O-O

If you continue with this all hell breaks loose for White:

[Event "?"]
[Site "?"]
[Date "?"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "?"]

[FEN ""]
1.Nf3 c5 2.c4 Nc6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 e6 6.g3 Qb6 7.Nb3 Ne5 8.e4 Bb4 9.Qe2 d6 10.f4 Nc6 11.Be3 Bxc3+ 12.bxc3 Qc7 13.Bg2 e5 14.c5 b6 15. cxb6 axb6 16. O-O Ba6 17. c4 Nd4

Bxc4 is always coming, Ng4 is possible at some point, and Nc2 is a possibility. You can always bring the Queen to c2 to force an exchange of material. White's light squared bishop is still not helping much. Don't forget about the dominating  center pawns. If you play on you'll definitely find Black up by material.

I will not say "always take towards center,” but it does help you most of the time.


About retrograde analysis Raymond Smullyan wrote some great books with Retrograde Analysis chess puzzles. I know of two, are there others?

Of course there are others!

For chess, there are many chess problems including retrograde analysis problems and many, many, many other types of problems that you would likely find interesting:

Retrograde Analysis - Problems that show a diagram and ask a question in which you must deduce the answer from the position.
Proof Games - Figure out how to get to the diagram from the starting position in a limited number of moves.
Help mates - Figure out how to checkmate black in a certain number of moves (you get to play both sides).
Reflex mates - figure out how to mate yourself given that each side must reply with mate in one if given the opportunity.
Series mates - Black makes a series of consecutive moves and then white mates in 1 move.
Studies - Usually orthodox chess endgame problems that demonstrate an interesting or important or impressive way to win.

There are journals or magazines that publish chess compositions and give out awards to the best problems. The best problems have an artistic quality which demonstrate a certain concept, have interesting interactions among pieces, or achieve some specific goal.

Every problem usually has a stipulation (what it is you are trying to accomplish) and conditions. A stipulation is what it is that you are must accomplish and the conditions are the set of rules that must be followed, which can be different than orthodox chess. Some problems use one more fairy pieces which are one of many non-standard pieces that move in a variety of different ways.

Basically, there are many chess problems (compositions) and composers (people who create them). A friend of mine introduced me to the world of chess problems and I've composed only a few myself. Here are just a few of the places you might find some more problems including retros:

The Problemist
Strategems (Proof Game and Retros Link)
FIDE Albums (FIDE actually gives out titles similar to GM/IM/FM for chess composers)

edit:

Since you already know what a retro is, here is an example of a famous helpmate.

[FEN "8/8/q7/8/1R4K1/k2N4/8/8 w - - 0 1"]
[White "Henry Forsberg"]
[Black "1935"]

Helpmate in two (black moves first and after two moves from each side, black is mated):

diagram
replace queen on a6 with a black rook
with a bishop
with a knight
with a pawn


Level the field when letting computers play against each other I just read this question and it made me wonder: when setting up such a game/comparison - shouldn't you try to level the computing capacity field? Or at least limit how much energy each "player" is allowed to use (and then let each team optimize within that limit). Otherwise, isn't it just a matter of building the biggest computer?

You absolutely should, which is why the two most important computer chess tournaments (CCC and TCEC) both make all competitors play on the "same" hardware. "Same" in inverted commas because the recent advent of neural-network engines like AlphaZero, which run best on GPUs, meant that it's no longer fair to play on exactly the same hardware for everyone.

You can see the result of not using equal hardware from the 2019 WCCC results, which Komodo won. Komodo is almost a hundred elo behind Stockfish when run on equal hardware (and Stockfish doesn't play in the WCCC, because it's not a commercial engine and doesn't have full-time staff to attend the event).

The situation right now is traditional engines run on the same CPUs, NN engines run on the same GPUs, and whenever traditional engines play against NN engines, they run on consensus fair hardware. "Fair" here is a very controversial word, because there are several different measures of what is fair that I'm glossing over. Suffice to say unless you are a hardware expert yourself, I'd just trust the admins of CCC and TCEC to use something that's fair.

Edit: to illustrate the impact of hardware, here's the list of hardware the competitors played at in the 2019 WCCC. Note Jonny ran on 1200 (!) cores, and it just barely edged out Ginkgo, which was running on 1/20 of the cores. In TCEC Season 14, the two engines played with the same hardware in Division 1, and Ginkgo comfortably finished ahead of Jonny in spite of multiple crashes (which happen because Ginkgo doesn't run well at 43 cores; they result in auto-losses).

You can also see that these games were played is Division 1, not even Division Premier. Many of the strongest engines in the world simply don't participate in WCCC. I don't know the exact reasons why, but I'm confident hardware is a major issue for participants. In turn, this lack of participation is partly why the community don't take the WCCC very seriously.


What is the theoretical assessment of this 4 knights gambit? [FEN ""]
1.e4 e5 2.Nf3 Nf6 3.Nc3 Nc6 4.g3 Nxe4!?

Some games have followed 5.Nxe4 d5 6.Nc3 d4 7.Nb1 e4 8.Ng1 for example.

At depth 19, Komodo gives an equal evaluation (+0) after 8.Ng1 (and according to Komodo all moves were best leading up to that point after 4...Nxe4). However, it says that 8.Nh4 gives White a +0.32 advantage.

It's hard to judge the theoretical assessment just by an engine's evaluation from the 8th move, but there are only a few games played in my database so there's not much to go on. Overall it seems absolutely playable for Black and funner to play from his side of the board. But objectively White probably has some slight advantage.


Why is 14..Qd8 the most popular move in this variation of the Caro Kann? According to chessbase, 14..Qd8 is by far the most popular continuation in this position (196 games), even though Stockfish 8 seems to prefer 14..Ngf6 (1 game).

I'm struggling to understand the rationale for 14..Qd8, as the queen looks reasonable on a5 for the time being (pinning the pawn on c3, which may allow tactics on d4), while 14..Ngf6 develops a critical piece which allows the black king to castle. Admittedly, after 14..Ngf6, the white attack on g7 can build up quickly with ideas of exchanging knights and then Qg4 and Rh3-g3, but black has defensive resources to deal with it and I fail to see how 14..Qd8 helps in any case.

[FEN ""]

1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Bf5 5. Ng3 Bg6 6. h4 h6 7. Nf3 Nd7
8. h5 Bh7 9. Bd3 Bxd3 10. Qxd3 e6 11. Bf4 Qa5+ 12. Bd2 Bb4 13. c3 Be7
14. Bf4 Qd8!? {+0.22 - most popular move}
( 14... Ngf6 { -0.14: Engine likes this better} )

This is ctg format property, or bug, if you like. There were no games played with 14.Bf4 and as well there were no games played with 14...Qd8. The ctg tree just knows position after 14...Qd8. Certainly it happens via different move order. So in 196 games wasn't played 14...Qd8, but 196 games saw the position arising after 14...Qd8.

This position arises in 11...Bb4+ 12.c3 Be7 line after move 12.

I dislike this ctg thing as it can hide a lot of refutations in move order sensitive lines. It navigates you towards most played positions, it doesn't show you the most played moves.


Where is the blunder that White made? [Event "the_meayhi vs. oxygen2020"]
[Site "Chess.com"]
[Date "2020-08-16"]
[White "the_meayhi"]
[Black "oxygen2020"]
[Result "1-0"]
[WhiteElo "810"]
[BlackElo "1032"]
[TimeControl "blitz"]
[Termination "the_meayhi won by resignation"]
[fen ""]

1. d4 d5 2. Bf4 c5 3. dxc5 e6 4. Bxb8 Rxb8 5. e3 Bxc5 6. Nc3 Ne7 7. Nf3 Bd6 8. Qd4 O-O 9. Bd3 a6 10. Qh4 g6 11. Ng5 h5 12. g4 Nf5 13. Bxf5 1-0

Despite the result of the game, te chess.com engine says that White blundered. It also says that one player was winning and blundered it away. What do those mean?

Your last move 13.Bxf5 leaves you with a much smaller advantage than 13.gxf5, that's what the engine is counting as a "blunder" (some of the previous moves have smaller mistakes, but none of them should be counted as "blunders")


Practical study for a former player? I played quite often in the mid 80's to mid 90's. My highest rating OTB was low 1300's (Edited, I had thought I reached 1415, but not according to USCF site-although that doesn't include my high school stuff in the 80's) under the USCF, with somewhat desultory study habits, although I did do a lot of reading on general tactics, pawn structures and some theory. Two best results were a round upset prize at the Western Open, and a $3000 check in the U1300 at the tournament in Vegas in December (Forgot the name).

I have been getting interested in playing again, and started looking at what is out there, and I'm a bit overwhelmed with the tools that are available now.

Where should I start? I'm probably way beyond most "pawns move one or two squares" beginner books, but probably not up to speed on even intermediate books, I vaguely remember bits of a couple openings, etc.

And, what openings should I concentrate on learning first, that will allow me to expand? IIRC, I played Scotch, French and was toying with the Indian openings.

I tried to phrase this so as not to encourage open ended debate, and I don't think it quite fits the suggested questions already existing. If it still is deemed too broad, make a couple suggestions and I can edit for fit.

I am going to make a few suggestions on reading material.

Pay a visit to Dan Heisman's column at Chess Cafe called the Novice Nook. Pay special attention to what he writes on the topic of Real Chess (article 1 and article two).

Focus as much as you can on this "Real Chess" idea in your studies and games. Always remember you will play the way you train. Therefore put a lot of training into proper over-the-board analysis. A book like Practical Chess Exercises can be useful for this as it has a mixture of tactical and positional positions so you are never certain if you should be looking for a forced sequence or a positional idea.

Honestly I would not spend a ton of time studying the openings. But software like Chess Position Trainer can help you a lot. As far as which ones, stick with the ones you enjoyed in the past and learn new ones that you see in your studies.

For literature I think Ludek Pachman's Modern Chess Strategy is probably one of the first books you should read. I also really like Silman's Complete Endgame Course: From Beginner To Master for fundamental endgame theory that is highly practical.


Can White engineer a winning breakthrough? I have managed to create a temporary "fortress" after losing the exchange. Analyzing the position after the game ended, I was able to find a plan for White to breakthrough. After further analysis I was able to find the defense for Black.

My "gut feeling" tells me that White should win anyway but I need help in finding the solution.

Below is the position:

[Title "White to move"]
[fen "r7/1kp2p2/1p1p3p/p2Pp1nP/P1R1PpP1/1PP2P2/4K3/R7 w - - 0 1"]

EDITED on July, 21th 2014 :

Since nobody ( not even engines! ) considered option of penetrating on the kingside with the King via light squares, I am submitting lines that can guide others when constructing their answers.

[Title "White to move"]
[fen "r7/1kp2p2/1p1p3p/p2Pp1nP/P1R1PpP1/1PP2P2/4K3/R7 w - - 0 1"]

1.b4 c5!? 2.dxc6+ Kc7 3.bxa5 bxa5 4.Rb1! Ra7 $8 5.Kf2! Ne6 6.Kg2! Ng5 ( 6...Nc5 7.Rxc5! dxc5 8.g5!+- Kxc6 ( 8...hxg5? 9.Rb7+ Rxb7 10.cxb7+- ) ( 8...Ra8 9.Rb7+ Kxc6 10.Rxf7 hxg5 11.h6 Kd6 12.h7 Ke6 13.Ra7! Rd8 14.Kh3 Kf6 15.Kg4 Kg6 16.Rxa5+- ) ( 8...f6 9.g6!?+- )  9.Rb8!+-  ) 7.Rb5! f6 ( 7...Ne6 8.g5!+- ) 8.Rb1! $22 Ne6 9.g5!! Nxg5 ( 9...fxg5 10.Rb7+! $8 Rxb7 11.cxb7 Kxb7 12.Kh3+- ) ( 9...hxg5 10.Rb7+ Rxb7 11.cxb7+ Kxb7 12.h6+- ) 10.Rb5! Ne6 11.Kh3 $22 Nc5 ( 11...Ng5+ 12.Kg4+- ) ( 11...Ng7 12.Kg4+- ) 12.Rcxc5!+- dxc5 13.Rb7+ Rxb7 14.cxb7 Kxb7 15.Kg4+-

Based on the above lines, I have tried to "sit in place", and came to the critical position where Black seems to hold:

[Title "White to move"]
[fen "r7/1kp2p2/1p1p3p/p2Pp1nP/P1R1PpP1/1PP2P2/4K3/R7 w - - 0 1"]

1.b4 f6 2.bxa5 Rxa5 $8 ( 2...bxa5? 3.Rb1+ Kc8 4.Rbb6! Kd7 5.Rb7+- ) 3.Rcb4 Nf7 4.c4 Nd8 5.Rb5! Rxb5 ( 5...Ra8 6.a5! ) 6.cxb5! $8 Nf7 7.Ra3! Ng5 8.Kd2 Kb8 ( 8...Nf7!? ) 9.Kc2 Kb7 10.Rc3! Nh7 11.Kb3 Nf8 12.Kb4 Nd7 13.a5 bxa5+ ( 13...Nc5!? 14.a6+! $8 Kb8 15.Kc4! Nd7 16.Kd3 Nc5+ $8 ( 16...Nf8 17.a7+!+- ) 17.Ke2 Ka7 $8 ( 17...Na4? 18.a7+!+- ) 18.Kf2 Kb8 $8 19.Kg2 Ka7 20.Kh3 Kb8 21.g5!+- fxg5 $8 22.Kg4 Ka7 23.Kf5 Kb8 24.Rc2!! Ka7 25.Rc1! Kb8 26.Rg1! Nb3 27.Rxg5!! Nd4+ 28.Kg4! Nxb5 29.Rg6 Ka7 ( 29...Nd4 30.Rxh6 b5 31.Rh7! b4 32.a7+! Kxa7 ( 32...Kb7 33.Rxc7+!+- ) 33.Rxc7+ Kb6 34.Rc1+- ) 30.Rxh6 Kxa6 31.Rh7 Kb7 ( 31...Nd4 32.Rxc7+- ) 32.h6 Nd4 33.Rg7+- ) 14.Kxa5

It seems that Black can indeed create an impregnable fortress. Sacrifice with b6 does not work, and knight will always be able to reach g5 in time to stop White king from penetrating via g5 sacrifice. If White sacrifices on g5 too early, Black will always have Nf6 and will move around his king, maintaining blockade. Lines where White sacrifices rook on g5 end bad since Black sacrifices the knight and has won pawn endgame.

I will investigate few more ideas ( like c5 sacrifice ), before I officially accepting an answer...

END OF EDIT

After 10 minutes, Stockfish says:

[FEN "r7/1kp2p2/1p1p3p/p2Pp1nP/P1R1PpP1/1PP2P2/4K3/R7 w - - 0 1"]

1.Rb1 c5 2.dxc6+ Kc7 3.b4 Ra7 4.Rb3 Ne6 5.Rb2 Ng5 6.Rb1 Ne6 7.b5 Ng5 8.Kf2 Ra8 9.Rd1 Ne6 10.Rd2 Nc5 11.Ke2 Ne6 12.Rd1 Rg8 13.Rc1 Ng5 14.Rh1 Ra8

...with the machine clearly not finding a plan. But what happens if we play a 'do nothing' move for Black's first move?

[FEN "r7/1kp2p2/1p1p3p/p2Pp1nP/P1R1PpP1/1PP2P2/4K3/R7 w - - 0 1"]

1.Rb1 f6 2.b4 Ra6 3.bxa5 Rxa5 4.Rb3 Ra8 5.Rcb4 Nf7 6.Ra3 Ra5 7.Rb5 Ka6 8.Ra1 Nd8 9.Kd3 Nf7 10.Rxa5+ Kxa5 11.Rb1 Ng5 12.Ke2 Ka6 13.Rb4 Ka7 14.Kf2 Nh7 15.Rb5 Ka6 16.Ke2 Ng5  (663.81)

White removes the Black Rook but then it gets pretty slow. Black's superb Knight and that weak f pawn are keeping Black in the game.

So what about the obvious 1.b4?

[FEN "r7/1kp2p2/1p1p3p/p2Pp1nP/P1R1PpP1/1PP2P2/4K3/R7 w - - 0 1"]

1.b4 f6 2.bxa5 Rxa5 3.Rb4 Rc5 4.Ra3 Ra5 5.Rb5 Ka6 6.Ra1 Nf7 7.c4 Nd8 8.Ra3 Nf7 9.Kd3 Ng5 10.Kd2 Nh3 11.Ra1 Ng5 12.Ke2 Nf7 13.Kf2 Nd8 14.Ke1 Nf7 15.Ra2 Ng5 16.Kf2 Nf7 17.Ra3

No dice.  Black looks solid.

From what I can see, Black holds.

EDIT

ALNS asked about this variation: 1.Rc6 Ne6! 2.g5 Nd8!? so I fired Stockfish back up.

I couldn't get past that hanging g-pawn, so the first variation is 1.Rc6 Ne6 2.g5. Stockfish used 4800 seconds on this (80 minutes).

[Title "1.Rc6 Ne6 2.g5"]
[fen "r7/1kp2p2/1p1p3p/p2Pp1nP/P1R1PpP1/1PP2P2/4K3/R7 w - - 0 1"]

1.Rc6 Ne6 2.g5 Nxg5 3.b4 Ne6 4.Rc4 Ng5 5.bxa5 Rxa5 6.Rb4 Nh7 7.Rbb1 Nf6 8.Kd3 Nxh5 9.Rh1 Nf6 10.Rxh6 Nd7 11.Rh8 Nc5+ 12.Kc4 Na6 13.Rf8 b5+ 14.Kb3 Nc5+ 15.Kb4 Rxa4+ 16.Rxa4 bxa4 17.Rh8 Kb6 18.Rh6 Kb7

So it's kinda sharp, but again it is hard to see how any progress will be made.  The position is rated .59 White's favor - the least favorable score for White for any variation we've discussed.

Now, on to the main variation 1.Rc6 Ne6 2.g5 Nd8

[Title "1.Rc6 Ne6 2.g5 Nd8"]
[fen "r7/1kp2p2/1p1p3p/p2Pp1nP/P1R1PpP1/1PP2P2/4K3/R7 w - - 0 1"]

1.Rc6 Ne6 2.g5 Nd8 3.Rc4 hxg5 4.h6 c5 5.h7 Nc6 6.dxc6+ Kxc6 7.Rh1 Rh8 8.Kf2 Kd7 9.Rh6 Ke7 10.Kg2 f6 11.Kf2 Ke6 12.Rh1 Ke7 13.Rh2 Ke6 14.Kg2 Kf7 15.Kf1 Ke7 16.Rh6 Kf7 17.Kf2

That's after almost 2 hours.  White is rated +3 and seems to be able to engineer a break on the Queenside. This is enough for a win. The Knight seems misplaced on d8.  I'd grab the pawn on g5 instead.

EDIT - ALNS has 2 more variations to look at

[Title "5... Ne6"]
[FEN "r7/1kp2p2/1p1p3p/p2Pp1nP/P1R1PpP1/1PP2P2/4K3/R7 w - - 0 1"]

1. Rc6 Ne6 2. g5 Nd8 3. Rc4 hxg5 4. h6 c5 5. h7 Ne6 6.dxe6 fxe6 7.Rh1 Rh8 8.Kd3 Kc7 9.b4 Kd7 10.bxa5 bxa5 11.Ke2 Kc6 12.Kd2 Kd7 13.Kd3 Ke8 14.Ke2 Kf7 15.Rd1 Rxh7 16.Rxd6 Rh2+ 17.Kf1 g4 18.fxg4 Ke7 19.Rc6 Kf6 20.R4xc5 Kg5 21.Rxe5+ Kxg4 22.Rcxe6 Kf3 23.Kg1 Rg2+ 24.Kh1 Rc2 25.Rxa5 Rxc3 26.Rf5 Rc1+ 27.Kh2

With, after several hours of processing, a healthy score of +7.5 in White's favor. Black is dead lost. I like to add complete variations to these threads, but all these moves are suspect after moves 4 or 5. In this variation, Black captures the pawn on h7 but in doing so allows White to run amok.  I don't care much for the Knight sacrifice; holding when down a full Rook is tough.

edit - 8.Kd3 is a killer move. Black can get the Rook with 8... d5 but after 9.Re4 dxe4 10. Kxe4 Black's king-side pawns all drop.

[Title "5. dxc6"]
[FEN "r7/1kp2p2/1p1p3p/p2Pp1nP/P1R1PpP1/1PP2P2/4K3/R7 w - - 0 1"]

1.Rc6 Ne6 2.g5 Nd8 3.Rc4 hxg5 4.h6 c5 5.dxc6 Nxc6 6.Rd1 Kc7 7.b4 Kd7 8.bxa5 Rxa5 9.h7 Ra8 10.Rb1 Kc7 11.Rh1 Rh8 12.Rh5 Kd7 13.Kd3 f6 14.Rh6 Kc7 15.Ke2 Kd7 16.Rh5 Kc7 17.Rh2 Kd7 18.Kd3 Kc7 19.Rh1 Kd7  (10405.71)

This comes up as +2.2 for White.  I don't like this because it allows the misplaced Knight on d8 to reposition with tempo. The simpler 5. h7 puts the pressure on Black and wins the Knight and then the game per the previous diagram.

EDIT
This is in regards to the "White King Infiltrates" variation mentioned in the OP's post.

[title "Infiltration"]
[FEN "r7/1kp2p2/1p1p3p/p2Pp1nP/P1R1PpP1/1PP2P2/4K3/R7 w - - 0 1"]

1.b4 c5 2.dxc6+ Kc7 3. bxa5?!+= (3.Rc1 Ne6 4.b5 Rg8 5.Rb1 Re8 6.Ra1 Ra8 7.Rd1 Rd8 8.Kf1 Ra8 9.Rd2 Nc5 10.Kf2 Ne6 11.Ke2 Rd8 12.Kf1 Ra8 13.Kf2 Nc5 14.Ke2 Ne6 15.Rb2 Rh8 16.Kf1 Rh7 17.Kf2 Nc5 18.Rd2 Rh8+/-) 3... bxa5 4. Rb1 Ra7 5.Kf2 Ne6 6. Kg2 Ng5 7.Rb5 f6 8. Rb1 Ne6?! ( 8...Nh7 9.Kf1 Ng5 10.Ke2 Ne6 11.Rb5 Ng5 12.Rb2 Ne6 13.Rd2 Ra8 14.Rd5 Ng5 15.Kf2 Nh3+ 16.Ke1 Ng1 17.Rd3 Nh3 18.Rd1 Ng5 19.Rb1 Ra7 20.Ke2+/-) 9. g5 Nxg5?! (9...fxg5 10.Kh3 Nc5 11.Kg4+/-) 10.Rb5 Ne6 11. Kh3 Nc5?? (11...Ng5+ 12.Kg4 Nh7 13.Kf5 Ng5 14.Kxf6 Nxf3 15.Rb2 Ng5 16.Kg7 f3 17.Kxh6 Ne6 18.Rb1 Nf4 19.Kg5+/-)

The variations show a significant deviation from what Stockfish thought was best. All variations except for the last indicate a move that loses perhaps a pawn. Black's 11th move is fatal, however.  The associated variation shows White with a moderate advantage.  Black can make White work for it.

FINAL EDIT

Here's Stockfish playing itself at 15 minutes per move.

[title "Granite is tasty"]
[FEN "r7/1kp2p2/1p1p3p/p2Pp1nP/P1R1PpP1/1PP2P2/4K3/R7 w - - 0 1"]

1.Rc6 Ne6 2.Kf1 f6 3.b4 Nd8 4.Rc4 Kc8 5.Kf2 Kd7 6.Rc1 Nf7 7.Ke2 Ra7 8.Rc2
Ra8 9.Ra2 Ra7 10.Ra1 Ra8 11.Kf1 Nd8 12.Ra2 Nf7 13.Kf2 Ra7 14.Ra1 Ra8 15.
Ke2 Nd8 16.Kd3 Nf7 17.Ra2 Ng5 18.Ke2 Nf7 19.Ra3 Nd8 20.Kf2 Nb7 21.Ra2 Nd8
22.Rc2 Nf7 23.Rc1 Ng5 24.Rc6 Nf7 25.Ke2 Nd8 26.Rc4 Nf7 27.Rc2 Kc8 28.Ke1 *

...with White clearly not finding a break-through. Black holds, thanks to that magnificent Knight... and White's Rook being bottled up.


Tricky continuation to the Fried Liver "refuted" Suppose white gets the following opening:
[FEN ""]
1. e4 e5
2. Nf3 Nc6
3. Bc4 Nf6
4. Ng5 d5
5. exd5 Na5

This is what I call Fried Liver Refuted, instead of Nxd5 we get instead Na5. From this position does white have some tricky continuation? By tricky I mean some sharp snappy line with some traps in it. It seems like after Na5 white runs out of tricks, but is this true? Some tricks in this position would be really fun to implement; most players only study this line up to this point because it is preached that Na5 is the best move for black and after it white runs out of punches, so a couple of tricks would most likely find black with is guard down.

I mean, this is the main line and for a reason.
But I would be very surprised if most people's repertoire ended here, this is where it begins. The line goes
6.Bb5+ c6 7.dxc6 bxc6
And now White has a number of options. In all of them White stays up a pawn however Black gets some counter play. (and there isn't a great line to give back that pawn for initiative, not much to play for tricks)
The two main moves are 8.Be2 and 8.Bd3.
The line might continue 8.Be2 h6 9.Nf3 e4 10.Ne5 and Black will keep some lead in development and try to attack.
The idea of the other move then is to gain access to the e4 square, if 8.Bd3 h6 9.Ne4.
However this move blocks the d pawn so White will need to move that bishop again at a later time. Both of these lines can be very complicated and sharp so White has to be careful.


How can I open a .cbh databse On my old windows-pc I created a database of my games on fritz 11 which I then uploaded to googledrive. The database is a .cbh file. My old computer broke and I'd like to re-open this database. As I have a mac, I got my roommate to download chessbase reader and sent him the database, but when trying to open it the message appeared

"new-database.cbh is not a database".

Does anyone know why this might have happened? Can anyone suggest something?

A .cbh file is not a complete database. A database in Chessbase format consists of multiple files.

To backup or transfer Chessbase databases between computers, you can either:

Backup in Chessbase to a .cbv file
Save games in portable PGN


Is the French Defence good against 1.e4 for tactical play? I usually play 1...e6 (French Defence) against 1.e4.

I love to play tactical games. Is the French opening good for me? My primary aim in a chess game is to develop an attack against the opponent's king as soon as possible ... Is the French Defence OK for that?

French defense is often thought of as solid positional defense. However, French defense can be used as tactical weapon and many GMs use it that way. See two games by Alexander Morozevich below. Therefore, you should be able to play attacking chess using the French. If the French is working out for you, play it!

Polgar-Morozevich:

[FEN ""]
[Event "Wijk aan Zee Corus"]
[Site "Wijk aan Zee NED"]
[Date "2000.01.18"]
[EventDate "2000.01.15"]
[Round "3"]
[Result "0-1"]
[White "Judit Polgar"]
[Black "Alexander Morozevich"]
[ECO "C11"]
[WhiteElo "2658"]
[BlackElo "2748"]
[PlyCount "72"]

1. e4 e6 2. d4 d5 3. Nc3 Nf6 4. Bg5 dxe4 5. Nxe4 Be7 6. Bxf6
gxf6 7. Nf3 a6 8. g3 b5 9. Bg2 Bb7 10. Qe2 Nd7 11. O-O O-O
12. Rad1 Bd5 13. Rfe1 Kh8 14. Nfd2 c6 15. c4 bxc4 16. Nxc4 a5
17. Nc3 Re8 18. Ne3 f5 19. Nc4 Qb8 20. Na4 Qb4 21. b3 Bf6
22. Qc2 Rg8 23. Qc1 Rg4 24. Ne5 Nxe5 25. dxe5 Be7 26. Rd3 Rag8
27. Red1 f4 28. Qc3 fxg3 29. hxg3 h5 30. Bxd5 cxd5 31. Rf3 Kg7
32. Qc7 h4 33. Kg2 hxg3 34. fxg3 Qe4 35. Qc3 Qe2+ 36. Kh3 Rg5
0-1

Adams-Morozevich:

[FEN ""]
[Event "Sparkassen Cat XXI"]
[Site "Dortmund GER"]
[Date "2001.07.21"]
[EventDate "2001.07.12"]
[Round "9"]
[Result "0-1"]
[White "Michael Adams"]
[Black "Alexander Morozevich"]
[ECO "C03"]
[WhiteElo "2744"]
[BlackElo "2749"]
[PlyCount "54"]

1. e4 e6 2. d4 d5 3. Nd2 Be7 4. e5 c5 5. dxc5 Nc6 6. Ngf3 Bxc5
7. Nb3 Bb6 8. Bd3 f6 9. Qe2 fxe5 10. Nxe5 Nf6 11. O-O Nxe5
12. Qxe5 O-O 13. Bg5 Bc7 14. Qd4 h6 15. Bh4 e5 16. Qc5 Be6
17. Rad1 Rc8 18. Qe3 e4 19. Bxe4 Bxh2+ 20. Kh1 Qd6 21. Bxf6
Bf4 22. Qf3 Rxf6 23. Bxd5 Be5 24. Bxb7 Qe7 25. Qe4 Rf5
26. Rfe1 Rf4 27. Qe3 Rh4+ 0-1


Does it make sense to use an online ELO-rating-test for a beginner as a monthly test tool in order to see my progress? I'm almost a beginner in the chess world who at the moment only plays online and watch various chess lectures on youtube.

I'm thinking about using http://www.elometer.net/
on a monthly basis in order to see my progress over time.

What are the pro and cons of doing that?

Well, the main problem with these tests is that they aren't reliable. They can only give you a rough indication of your playing strength, nothing more. Maybe something accurate to 100 rating points, and it's very hard to gain 100 points in a month, even for a beginner. So it will be hard to measure your progress on that scale.

Also, taking the same test over and over again makes you recognize certain test questions, instead of solving them with pure chess skills. And lastly, they measure your ability to solve chess diagrams, instead of your playing strength. That encompasses many more things like an opening repertoire, knowing how to spend your time over the game, etc.


Arena Chess playing with the engines Can someone show me how to stop arena engine from showing lines that he is intending to play while we play rated games? Thanks in advance

Right click on the window where moves are displayed -> show/display -> click on comments.
Now the engine output should be disabled.


How bad is 1. e4 c5 2. Nf3 d6 3. a3? Is this move clearly losing for white? Chessgames.com shows 1 win and 2 losses for white only, and I could not find any other reference for this move.

[FEN ""]

 1. e4 c5 2. Nf3 d6 3. a3?

No, it is not clearly losing, but I would say that the question mark is appropriate. You have to understand that white, by the nature of going first, can afford to waste a move in many early opening positions without it being a losing move. What it does though is it usually throws away any chance at gaining an advantage, and that is because you cannot be sure that the wasted move, in this case 3.a3?, will be helpful to your position as the position develops. In general, in the opening, you want to play moves that you KNOW will help you and that you know you want to play...you cannot know that about a3. a3 also does nothing to fight for the center. At best, you might play an early b4 trying to get play in the Wing Gambit.

In the Mega Database, there are actually 35 games, but the average rating for white and black is only 1796 to 1768, so that should tell you a lot: Strong players do not think it is good, even if not losing. For the record, white only scores a 37.1% with 3.a3?, but again, anything can happen between 1700s.


Compile StockFish optimized for arm64-v8a I cloned StockFish from GitHub and did a make inside the src folder and found that supported archs are:

x86-64-bmi2             > x86 64-bit with pext support (also enables SSE4)
x86-64-modern           > x86 64-bit with popcnt support (also enables SSE3)
x86-64                  > x86 64-bit generic
x86-32                  > x86 32-bit (also enables SSE)
x86-32-old              > x86 32-bit fall back for old hardware
ppc-64                  > PPC 64-bit
ppc-32                  > PPC 32-bit
armv7                   > ARMv7 32-bit
general-64              > unspecified 64-bit
general-32              > unspecified 32-bit

I want to build as optimized as possible for my samsung galaxy s10+ running having an arm64-v8a exynos9820 processor.
Which archs should I choose? Will they be optimized as they could be when I build  for x86-64-bmi2 for my 64bits ubuntu? If not, how could I optimize them?
(The rather simple idea is that I want to build it to have it as optimized as possible for my mobile phone.)

https://forum.armbian.com/topic/9862-info-how-to-compile-the-actual-64bit-version-of-stockfish-chess-engine/

Seems to show that you have to hack it to get it to compile at all.


How often do hash collisions occur in modern chess engines? This is a question I am asking for a chess engine I am attempting to create.
I have read that engines like Stockfish can look at around 100 million positions per second on a good computer. The code on GitHub (line 104) shows that Stockfish uses "uint64_t", a 64-bit int for hash keys. This Wikipedia page shows that for a hash table with 64 bit entries (4th line reading down), the probability of a collision after 6.1×10^8=600 million hashes (in the p=0.01 column) is 1%.
So at 100 million positions per second, giving the engine 6 seconds per half-move, 600 million positions would be analyzed for each half-move. A collision would occur 1 in every 100 half-moves. Thus, a collision would happen about once per game (50 moves per game seems roughly typical).
Am I missing something?

Generally the answer is, that there has been a patch from some developer of the community in the past, which happened to be an improvement over the status quo after tight statistically sound testing and this is usually accepted without questions, even if the change appears illogical to some.
It is known that a high collision rate must not be detremial for a chess engine. Bob Hyatt (author of "crafty") had written a paper about it a long time ago (https://craftychess.com/hyatt/collisions.html).
Stockfish uses a variable sized hash table (cluster granularity) with clusters of 32 bytes having 3 entries of size 10 byte each(https://github.com/official-stockfish/Stockfish/blob/master/src/tt.h#L68). Each cluster entry stores only 16 bit of the original zobrist key (https://github.com/official-stockfish/Stockfish/blob/master/src/tt.h#L51).
Another similar point is, that stockfish uses no locks to access the table, technically that means it is racy, that means 100% undefined behaviour. Every entry is carefully validated before use instead and given that a racy access simply returns an potential erroneus value, this would work even if every hash table access would return random numbers, at least this is the idea. As a side note, if there is some pedagocical language lawyer around reading this, please don't tell us stockfish could format our hard drives, we know it and are awaiting it with composure.
The first one to show this technique was AFAIK again Hyatt (https://craftychess.com/hyatt/hashing.html).
We see that wrong hash values are absolutely no problem for stockfish, all that matters is what happens most of the time. All entries are reevaluated fully at the next iteration and can only cost search time.


multi pv mode in GUI is their any facility in babas chess (4.0) to facilitate multi pv mode. babas chess that i have only shows single pv. if it doesn't then which GUI (free) has facility for the multi pv mode running for pc.

While I don't use Babas chess, I'm sure Chessbase and Arena support multi-pv.


Where can I find details of future tournaments? I have never taken part in an OTB tournament (Simply put, I am not FIDE rated), and I want to. But, I can't find any tournaments to play in. I am currently resident in Sudan. Is there a website where I can find all details of a tournament (location, start date, end date, requirements, etc...)?. Please do not recommend the FIDE website; I always go there and only find finished tournaments.

One of the options is Chess Results, but even though there are some future events, probably most of the listed events will be already finished tournaments (like now).

But you can try it in the future. Just search by your federation and do the tournament selection:

Another possibility is ChessMix Calendar. There seem to be a lot of events but the problem is that most of the search (almost everything) is available only for subscribers (who paid the $25/year fee).

My next try would be The Week in Chess (TWIC) calendar, althought it is not searchable at all and most of the events are located in Europe.

You might also consider giving a "Like" to some Facebook sites like Africa Chess Confederation that announce some competitions every now and then.


Is there a chess engine that does NOT use brute-force search? Every chess engine I've ever heard of (including all I found listed on Wikipedia) uses brute-force search with an evaluation function (minmax algorithm) to decide on its move.

This is not how most humans approach the game, employing general pattern recognition instead, so in principle, it would be possible for computers to do the same.

Is there any chess engine that does not rely on the brute-force approach to find its moves?

There were attempts back in the 1980s to write chess engines with knowledge bases that would pick candidate moves like humans, but they were unsuccessful. The problem is that human pattern matching is difficult to put into words, so creating the rules for the knowledge base was extremely difficult.

Training a neural network to pick candidate moves seems like a promising line of research. Here and here might be two pertinent papers. (FWIW, It is not my field of Comp Sci)


Why can't knights lose tempo? From Wikipedia: Kings, queens, bishops, and rooks can lose a tempo; a knight cannot (Müller & Pajeken 2008:40,175,189).

Is there truth to this? Examples please. My context is towards developing an engine eval.

Looking at a fen alone? Can we derive any info about tempo?

Is it only about minimizing distances?

In an engine, should we penalize moves that return to old squares? For opening or middle game?

Is having initiative more important than tempo gains?

If a player sees a possible  future where he will be in zug·zwang can the preempt with some tempo tricks like triangulation? Examples please?

I see tempo gains as more of a tool for teaching. Not really having much use in the game.

You seem to get the meaning/importance of tempo a bit wrong - it's not about getting back to the old square, it's about losing one move during the process, thus forcing the opponent to make his turn when it puts him in worse situation (this is called Zugzwang). This is especially important in endgames, and you can see some examples in the same wiki article you are referring to.

Also note that the final square doesn't have to be the same as the starting one (e.g. Re1-e2-e3 instead of Re1-e3), although it often is (mainly in Kings' triangulation). Knight cannot do any of that, as mentioned in answer by @magd. Knight can just jump from and back to the same square, but the opponent can e.g. also do some repetitive move and you end up right where you started. Knight just cannot take the route to its' destination which will lose exactly one tempo (or any other odd number).

But all other pieces (even pawns if they are at their starting square) can take an extra move while going to the destination, which in many situations enables you to force the opponent to make a move when it's a bad time for him. Triangulation is a classic example of this tactic.

Generally speaking, losing tempo or just getting back to the previous square is usually bad in openings or even middlegame, although that depends on the situation. But in the endgame, deliberate loss of tempo is often maneuver which wins you the game (of course, if situation requires so).

An example from wiki:

[fen "8/1p1k4/1P6/2PK4/8/8/8/8 w - - 0 1"]

If black would be on the move in this position, it would be clear victory for white, as after black King moves away, white can proceed either with his King or his Pawn (depending on the move). But white is on the move, so he must think of a way how to make it work. The answer is, lose a tempo with triangulation:

[fen "8/1p1k4/1P6/2PK4/8/8/8/8 w - - 0 1"]

1. Ke5 Kc6 2. Kd4 Kd7 3. Kd5

And now black is on the move, which enables white to break through.

You are right in saying that loss of tempo is used "only" to put opponent in zugzwang, but the importance of this is greater than it might seem at first. For example, every classic mate endgame uses loss of tempo and zugzwang to get the opponent's King to the edge of the board and to mate him. You often use zugzwang without even realising that you used it. Look at the mate with Rook:

[fen "1k6/7R/2K5/8/8/8/8/8 w - - 0 1"]

1. Rg7 Ka8 2. Kb6 Kb8 3. Rg8#

You aim to get your King to b6 when black King is on b8, so you can mate with Rook on 8th row. But you can't do that right away, as after 1. Kb6, black would get away with Kc8, and 1. Rh8+ would enable black to get away with Ka7. So in the process of getting to 8th row with your Rook, you deliberately lose a tempo with 1. Rg7 in order to win the game.

In contrast, to address your original question, Knight is not able to do that:

[fen "8/8/8/8/8/7p/5K2/5N1k w - - 0 1"]

1. Ng3+ Kh2 2. Nf1+ Kh1

If white could just get to the starting position with black on the move, it would be a quick victory (1... h2 2. Ng3#), but Knight can't lose a tempo, so it's impossible, which is why this position with white to move is a draw.


What do we know about how to get better at chess? When players here ask about getting better, there are frequent suggestions like "solve more puzzles", "study endgames", "read books", etc. But what do we know from a science perspective about getting better at chess?
A Google Scholar search for "psychology learning chess" turns up over 120,000 results, including an article from 1907 on "The psychology of chess and learning to play it."
What do we know from the scientific literature about the most effective ways to get better at chess, limits to the speed of improvement, etc?

There is a 2006 paper "Training in chess: A scientific approach" by Dr. Gobet from the University of Nottingham, and Dr. Jansen from Carnegie Mellon University, which goal was "...to show how recent findings in cognitive psychology can be applied to improve techniques of chess training, teaching, and learning"
It concludes that learning occurs best:

from the simple to the complex
when the elements to be learnt are clearly identified
when following an "improving spiral"  (this is similar to what DeGroot found in how a chess player thinks with progressive deepening).

Then using the above knowledge the authors used their "template theory" and used it to review various chess training techniques.
Some conclusions they get doing that are:
(in the area of Explicit Knowledge)

focus on a limited number of positions and openings and learn the various methods in these positions thoroughly.
repetition will be necessary.
avoid too much historical and anecdotal details.

(in the area of Implicit Knowledge)

Using a computer to view variations can greatly cut down on the time to do so, but may offer less efficient encoding of the information [in your brain].
Find a balance between rote learning and understanding (specifically in studying the opening).
study openings from different points of view -- for example, by linking it to the middlegame or endgame.
use a chess database for your repertoire as "memory is fallible!) and you will need to review it frequently.

They also mention the "decomposition method" which consists of studying and playing basic endgame positions -- basically removing most the pieces from the board in common middlegame structures.
In studying endgames the claim the "improving spiral" can be best applied.  I would compare this to how endgame table-bases are being created; basically solving the game backwards.
In studying tactics they suggest starting by themes and only later random.
They also defy some previous claims like "go through each variation once" and "blindfold chess is good for your chess"; going as far to say blindfold chess may actually be harmful to one's development.
They also think that studying composed puzzles is useless.
They then reiterate DeGroot's earlier findings on the importance of "pattern recognition".
As the paper was built on past studies I think it pretty much shows what scholars think of how chess learning should be approached scientifically.
Personally, I agree with their suggestion of studying in chunks and repetition.  It is easy to get overloaded when studying chess.


What do these numbers mean on chess.com? What do the numbers in the top right corner signify?

Those are the times taken for the moves.
So e4 took 0.1 seconds,
e5 took 6.2 seconds and
Nf3 took 7.7 seconds.


Chess dot com says this was my best move yet I don't have a clue why Whites turn the analyzer suggests that my best move is Nxe5
I really don't see why as I would just be trading away my knight for a pawn I don't see why this would be a good move

Black has an undeveloped queenside, a weak bishop on g7, lots of weaknesses on the light squares and consequently a very weak king position. This suggests potential tactics.

The point of 1. Nxe5 is that it opens the way for the white queen to h5. Together with the white bishop on c4 this should remind you of Scholar's mate or variations of it. Even though you don't end up with immediate mate here, the position with the white queen and bishop entering black's position looks extremely dangerous for black and moves like Nxe5 or potentially moving the knight to other squares should certainly be considered.

Concretely, whichever way black captures the knight on e5 (dxe5 or fxe5), white can regain material by 2. Qh5+ Kd7 (2...Kf8 or 2...Ke7 are answered with 3 Qf7 mate) 3. Qg4+ Kc6 (or Ke8) 4. Qxg7 and end up with a winning position due to the extremely weak black king.

If black does not capture the knight on e5, white still has a decisive advantage due to threats like Nf7 and its dominance on the light squares. Also white is up a pawn, though that is not essential here.


How important is castling? How much is it worth? Are there some statistical values for the worth of castling? Are there some numbers, for example in centipawn that can represent the value of castling?

Yes there are some numbers that can (sort of) represent the value of castling.

If you let Stockfish or any other strong engine analyze the starting position, it will generally come to the conclusion that White has roughly a +0.50 advantage. But if you use an opening book (1. Nf3 Nf6 2. Rg1 Ng8 3. Rh1 Nf6 4. Ng1 Ng8 5. Nc3 Nf6 6. Rb1 Ng8 7. Ra1 Nf6 8. Nb1 Ng8) which lets Black castle but not White, the advantage actually flips around, and the starting position advantages Black.

Check these games out:

Stockfish-Xiphos. The starting position, except White can't castle while Black can. Stockfish's starting eval at depth 31/48 is -0.20. (Yes Stockfish wins anyway, but it is Stockfish, the strongest conventional engine in the world, playing)
Xiphos-Stockfish. The reverse game. Xiphos plays 1. Nc3 evaluating the position as 0.00, while Stockfish is -0.84 at depth 36/52.
AllieStein-Stockfish. Played from the opening position with both sides able to castle. AllieStein gave 0.43 advantage to White at depth 18/57.
Stockfish-Alliestein. The reverse game, Stockfish gave White a 0.47 advantage in the opening position at depth 38/59.


Is there a chess engine that allows you to specify which opening it uses? I would like to practice against a particular opening - outside of bribing smart guinea pigs who know how to play chess, is there any way I can get opponents who always use a certain opening?

A great way of practicing your opening with a chess engine can be found on chess.com. You can create a free account, then go to the Learn Tab -> Book Openings -> Find the opening you want to practice -> Play Opening vs. Computer. You also have the chance to change the computer's difficulty level and what side you play.


Do you sign papers when joining a chess club? I've been invited by a club to join. I've never played  in a club before. He said I should sign papers, and then I can play for fun and free and represent the club in tournaments.

My question is, do you sign a contract or some papers when joining a club? The reason I'm worried is because in my country it's common for football and Volley-ball clubs to seduce the youth into signing life long contracts.  (maybe against the law but few go to court to demand justice, and  most of the times the clubs win the case)

My uncle was the best volley-ball player in the country, now retired, signed a life long contract and couldn't go to other clubs because his club refused to release his contract. My friend has signed a similar contract with a youth football team and now he can't join a professional team so he quit football (soccer).

I have other concerns as well, for instance the club plays most of the times afternoon, I have university or maybe I don't want to go, maybe I prefer playing Xbox  at home.

I mean if joining a club is just for fun, then why signing a contract? Signing a contract is the exact opposite of having fun. And chess is an individual game. Besides, if he wants me to sign, so he can coach me, I don't need coaching, I'm satisfied with my level of chess and all I want is to have fun if my free time by joining a club.

If he wants my signature to make sure I don't join another club, then it's none of his business, I'm leaving my country soon and when I do so, I will join another club. I want no strings attached, otherwise I prefer to play online.

So when you join a club do you sign papers? If so what do you look for when reading the contracts? Is there anything I should be concerned about.

Yes, usually you sign papers when you join a club. After all you commit yourself to paying the membership fee (even if in your case there is none) and for a financial commitment there has to be some kind of legal foundation. And there are other issues like whether it is allowed to play for several clubs, whether you get a national rating or an Elo and what happens with your personal data in that case.

But this shouldn't be a big deal. If the contract is a very long and complicated affair, I would get suspicious, too. Best take the contract home and show it to your parents, or somebody who can assess it.

Edit: This is the way it is usually done in Germany. But clubs are taken very seriously in our country. ;-) And our chess league system is really very thoroughly organised, so maybe that plays a role as well. Basically every club has a set of rules, pretty much like a democratic constitution, which you have to accept by signing. And although you can be a member of many clubs, you can only be an "active" member of one club at a time, so that is usually specified in the application form as well. (Except when you are a women, then you can be "active" for the normal league system for one club, and "active" in the women's league for another club …). Then you have to agree that your personal data is used for all kinds of nefarious purposes (like rating), and possibly acknowledge that it will take x month to end the membership (So if you end the membership too late, another payment is due).


What is the most effective way of reducing blunders? Many people suggest tactical exercises as the best form of study for this purpose but I find that it only attacks the problem from one dimension (not making the strongest in a position). Analyzing my own games I find that I'm much more likely to lose a game by making a dumb blunder rather than missing a winning combination, so solving more chess puzzles doesn't seem very effective at improving that. Any other forms of exercise that could help with this?

If you want to avoid "dumb blunders" - i.e. just dropping a piece you've left hanging on the other side of the board - a simple method is to take an inventory of the position before you do anything else on each move. Checking which of your pieces are attacked and which of your pieces are hanging would be a good start. The brain will catalogue this information into 8x8-grid punch-card type patterns in your head that act as a warning system against stupid errors.

It can however be surprisingly difficult to take a regimented approach like this even if on the surface it seems quite a trivial task to complete at the start of each of your moves. The brain has a tendency to immediately want to investigate interesting lines and will wander sometimes never to return. Even harder if you're an older player who has never applied such discipline.

But if you stick at it over time it becomes second nature and you just see better and don't blunder as much.


Being an Anti-Sicilian vs. Sicilian player So I have been developing my opening repertoire on ChessBase recently and established that, as a 1.e4 player, I have to properly memorize Open Sicilian main line, Dragon, Hyper Dragon, Taimanov, Löwenthal, Kalashnikov ,Sveshnikov , O'kelly, Najdorf , and surely some others ones which I am missing.
Wouldn't it be better for me to just master one anti-Sicilian line like for instance the Grand Prix Attack ? Indeed, from the Lichess 2000-2200 ELO games database, here are the win rates associated with the opening 1.e4 c5 2.Nc3 d6 3.f4, i.e., the Grand Prix Attack

This looks like a pretty good weapon for white if you ask me and avoids having to memorize literally a constellation of lines in the Sicilian.

My question is, are there any benefits for me to carry on playing the normal lines of the Sicilian and undergoing all the required memorization or should I convert to being an anti-Sicilian player ? What are the pros and cons ?

Additional information in light of my question

I am not a Sicilian player myself as black
I intend on pursuing a mastery title in chess
I nevertheless like playing Sicilian lines as white
I like memorizing lines but I also want to improve my ELO as fast/high as possible

The first question that needs answering is the following: what is your current playing level? The Grand Prix, and other anti-sicilians as well, can be a good way to trip up some sicilian players at lower to intermediate levels, but once your level of play gets higher these anti-sicilians will start getting less and less successful; there is a reason why they aren't the main lines after all.
But there is another aspect to this besides the result-oriented one, and that is your observation that many of these anti-sicilians require less memorization from the white player than the main lines in the open sicilian. At lower to intermediate levels this can be a good thing, since it means you can spend more of your time learning to play the middlegame and endgame properly rather than being tempted into thinking that studying more opening theory will bring you great levels of success. Another positive aspect of trying these anti-sicilians out is that you may encounter some nonstandard structures that you enjoy playing; this can prove very useful when trying to get to know oneself as a player. One final positive point in trying these lines out is that they will give you some indications as to why the main lines are what they are.
I would say that since these lines don't require as much study to pick up as the main lines, there is no real harm in trying them out. But you have to remember that they are a far cry from a silver bullet to the sicilian, and you should keep a flexible attitude about your choice of opening lines. Don't lock yourself to one specific set of lines to use for the rest of your career at this point when you haven't even reached master level yet. If you want to reach master level there is a high chance that you will eventually have to strongly consider adding some of the main lines to your repertoire, but this is something that can be done later. (who knows, maybe you end up adopting 1.d4 in the future?)
Although I don't think there is any harm in trying out slightly less common lines, I don't think it's bad to stick with the main lines either. One thing that you have to be very careful with is of course the risk of over-reliance on concrete lines. Don't just memorize the main lines thinking that you've learned them properly; after all, once you're out of the opening there is still an entire game left to be played, and if you don't know how to play these resulting positions you might as well not learn any theory at all. To understand these complex variations properly you need to play them many times, preferably against strong opponents, so that you can gain an appreciation of why the main lines are the way they are. You will also need to be able to find the optimal ways of playing when your opponent deviates from the main lines, and I will say the following: this is way, way harder to do consistently than it seems, so I will once again urge you not to place the memorization of main lines on a pedestal.
It may seem like the things I stated in the previous paragraph suggest that playing the main lines requires far too much work on your part, but this is not something that I wish to convey. While memorizing some lines is important in the open sicilian, I would say that the amount you need to actually memorize is less than you may think. You can get by surprisingly well with a shallow knowledge of concrete lines if you begin your study by going wide rather than deep; learn the basic gist of the lines (i.e., try to learn the main plans in broad strokes), and start playing as much as possible so that you can see how the plans work in action. Naturally you will have to learn your lines deeper and more concretely at some point, but if you have a solid foundation based on experience this will become a lot easier. Also, if you have experience playing without knowing the exact lines, it will be easier to play once you inevitably end up in a position that you haven't studied before.


Response to King's fianchetto opening Currently I am facing some difficulties playing as black when my opponent plays 1.g3.
In the midgame actually my position gets cramped. Is there some strong response to 1.g3? I actually want some good defense lines to counter 1.g3.

Many responses will be good against g3 - if you have problems against it  - actually its indicator that you have problems with general chess principles, so just study chess, get some good book on middle-game strategy and don't think of g3 for now. g3 is very slow and has no real opening threat for black - it takes on middle-game understanding though.


What are good openings for bullet chess? It is evident that bullet chess has a different set of strategies from regular chess. It follows, therefore, that certain openings will be better or worse relative to their normal chess counterparts.  Hikaru Nakamura covers some examples in his book "One Minute to Mate", but the coverage is very light.  What are some good bullet chess openings that are particularly strong due to the nature of bullet chess?

The best bullet players can and do play standard openings.  The openings are theory because they are the best moves.

If you want to play something different, there are a few justifications.  If you play certain moves all the time, you can often make the moves faster and gain time on the clock.  Similarly, if you play something off-beat, you will most likely know some plans from the position and often have a better understanding than your opponent.

With that lead in, one of the simplest openings to play is to fianchetto both bishops, play e3 and d3, and bring the knights to d2 and e2 (not necessarily in that order).  There is very little going on in the first 8 moves, so you won't have to look hard for tactics.  The downside is that you give your opponent a large space advantage.

The main plans of this opening are to develop all of your minor pieces and then decide to play either c4 or f4 depending on how your opponent has deployed his or her forces.  You can castle (usually kingside) and then just play chess.

Personally, I have always had better success in online chess (especially bullet) playing standard openings.  Play openings that you are comfortable with, and you will be able to take advantage of your whole sum of chess knowledge, as opposed to just utilizing bullet "tricks".

While it is beyond the scope of this question, one of the best ways to improve at bullet is to work on playing better and faster when both players have 10 seconds.  Most games are won or lost in this time frame.


Why did the computer win? I just played chess on my mac and the computer (black) won. Here's the final board:

Why couldn't I, white, use my king (D4) to take the black queen (C5)?

Because the queen is protected by the bishop on A3. Therefore its checkmate.


How can I get multiple computer recommended lines in python-chess module? In python-chess you can communicate with the engine on a given position. However the method presented in https://python-chess.readthedocs.io/en/latest/uci.html using the engine.go() function with only a time parameter returns just one continuation and that continuations evaluation.

I know in most chess programs you can see the top few ranked positions and their evaluations. How can I do the same in python chess? None of the parameters in engine.go seemed to let me do that.

You can do this by sending out MultiPV, something like:

engine = chess.uci.popen_engine(...)
engine.setoption({ "MultiPV" : multiPV})

The module will generate multiple lines for you, as an array.


What are some examples of wins by a much weaker player? I'd like to study examples where a much weaker player succeeded against an IM or GM.

In 2009, GM Nurlan Ibrayev of Kazakhstan (rated 2407 at the time) lost a classical time control game to 9-year-old Hetul Shah of India, who then had a FIDE rating of 1817. Shah's current rating, now three years after that game, is 1979, not so much higher than it was at the time of his upset victory. So this game wasn't a case of Ibrayev running up against some seriously underrated prodigy whose rating was about to shoot up several hundred points. To the contrary, this seems to be exactly the sort of game you are after: a much weaker player having a good day and taking a grandmaster scalp, with the black pieces no less!

[FEN ""]
[Event "7th Parsvnath International Open"]
[Site "Delhi"]
[Date "2009.01.11"]
[EventDate "2009.01.11"]
[Round "1.36"]
[Result "0-1"]
[White "Nurlan Ibrayev"]
[Black "Hetul Shah"]
[WhiteElo "2407"]
[BlackElo "1817"]
[PlyCount "88"]

1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.O-O Be7 6.Re1 b5 7.Bb3 d6 8.c3 O-O
9.h3 Na5 10.Bc2 c5 11.d4 Qc7 12.Nbd2 cxd4 13.cxd4 Bd7 14.Nf1 Rfc8 15.Ne3 Nc6
16.a3 Bf8 17.b3 Nxd4 18.Nxd4 Qc3 19.Ne2 Qxa1 20.Qd2 d5 21.b4 d4 22.Nd1 Rxc2
23.Qxc2 Rc8 24.Qd2 Nxe4 25.Qd3 Nd6 26.Bb2 Qa2 27.f4 Qc4 28.Qb1 d3 29.Ne3 Qe4
30.Nc3 Qxf4 31.Ncd5 Qg3 32.Nf1 Qg6 33.Bxe5 Nc4 34.Nf4 Qb6+ 35.Kh1 Nxe5 36.Rxe5
Bd6 37.Re4 Bc6 38.Qc1 Qb7 39.Re1 Bxg2+ 40.Nxg2 Rxc1 41.Rxc1 Bf4 42.Rc3 d2
43.Rd3 h6 44.Kg1 Qb6+ 0-1


Is my improvement decent, and if so how can I keep it up? This question may seem vain, since I'll talk about my improvement on chess, but I really want to have a measure of my learning curve and a notion of whether it is bad, regular, good or excellent, how to improve it if it's not excellent and how to keep it excellent if it is. So this is all about chess learning.

I know the rules of chess since the age of 4, but never played it often. I probably played around ten games from the time I was four to the time I was 21 (never even had a chessboard at my home), when I really started playing (this was June past year, so ten months ago).

I really started playing as I said on June 2019. I created a Lichess account and was rated 1100 on Classical chess. Ten months later, I am rated above 2200, so I gained over 1100 rating points in less than a year. I'm proud of this improvement, but I don't really have any comparison standards, so maybe it's a regular rate. I don't really know.

On the other hand, my Blitz rating is still quite low in comparison to Classic: a little bit above 1600. So my improvement has not been the same when it comes to thinking fast or mere intuition, since clearly I need to have a fair amount of time to find the right moves.

I'm really invested at becoming a CM, so analyzing and understanding my learning-curve and improvement rate is very important for me. I dedicate a lot of time to chess (studying and playing), and I want to know how much that's paying off.

If my improvement is below good (since let's face it, at Blitz I'm still simply weak), how can I accelerate it, specially on fast time formats? If my improvement is decent, how can I keep pushing further? Because now that I'm above 2200 Classic elo I'm beginning to face very strong players (I played my first titled opponent recently) and I want to keep up with them.

Sorry if my question is vague, I hope you can appreciate how important it is to me to understand myself in regards to my chess learning.

Going from a beginner to being rated 2200 on Lichess in a year is a very good rate of improvement. Would you mind elaborating on what you did to get there?

Still, a Lichess rating isn't always an accurate representation of strength, and it's possible you could be somewhere between 1600-1800 ELO over the board. The only way to find out is to play rated games OTB and see. This could be useful in figuring out how to continue your training.

For continuing, it seems like whatever you're doing is working well (I wouldn't worry about trying to accelerate your progress, if anything it will start to decelerate soon). If you really are 2000-2200 strength, you could consider getting the GM Preparation books from Quality Chess. The Great Predecessors series by Kasparov is also recommended. In addition, you should put together a solid opening repertoire, perhaps using Chessbase. You can buy opening books to do this, or research on your own (you might need help at first if you've never done it before). A good endgame book would be useful as well. I assume you're already doing this, but solving online tactics is important for sharpening your tactical intuition. You could also consider finding a coach in your area, but this depends on how much you want to spend to reach your goals.

Most titled players took years to get where they are, so I wouldn't give yourself the pressure of reaching their level so quickly. For example, I only got my FM title after playing for roughly 12 years. Building up a good intuition (which helps in blitz) comes from lots of practice, and isn't really something that can be gained very quickly.


When is a good time to double rooks? When analysing my games with an engine (Stockfish 8) I found that I quite frequently miss when the engine thinks it would be a good idea/time to move a rook to the second rank to double up (I guess).

I had a short search on YouTube to find some material on the topic and couldn't find one at first glance.

Do you guys have any recommendations on how to recognise when the position allows/favours bringing rooks into position?

Maybe its a naive question but I'll give it a try anyway since I consider myself somewhat of an intermediate beginner.

You may consider doubling rooks if:

There is an important open-file, and you want to make sure you have firm control on it. You want to minimize your opponent's controls to the file. (very common).
There is a semi-open file with an isolated or backward pawn. The pawn is protected by your opponent's rook. You want to win it. (very common)
If you want to exchange both rooks.
If you want to improve the position of your rooks. In particular if no other good squares for the rooks to go.
You have something to pin on the open-file, and you want to win it (look at the game below)

You may want to study the classical game between Alekhine and Nimzowitsch. Look at the final position:

  http://www.chessgames.com/perl/chessgame?gid=1012683&kpage=1

Here, you have absolutely no reason not to double your rooks for both sides. Nimzowitsch had to double to protect his c6 knight. Alekhine had to double his rooks to win the c6 knight. Note there is an open c-file and no any other good squares for the rooks.


Who is better here? [hard] Who is better in this position? White or black? Hard one!

This is indeed an interesting position. I am assuming it is black to move because the highlighted knight move should be the last one, and also because otherwise black would lose their queen for no good reason.

It seems that white manages to get some compensation by forcing black to exchange their queen for a rook. However, the evaluation still favors black by a bit less than -2. Anyway, the ending looks very difficult to convert.

This analysis is according to Stockfish 9 at depth 22:

[FEN "r2q2k1/pp3Npp/1np1b3/2Q5/3r4/2N5/PP4PP/4RRK1 b Qq - 0 1"]
[Startply "0"]

1... Bxf7 2. Re7 Bc4 3. Qg5 g6 4. Qe5 Qxe7 5. Qxe7 Rd7 6. Qe1 Bxf1 7. Kxf1 Nd5


Vienna Gambit vs King' Gambit The Vienna game/gambit goes as 1. e4 e5 2. Nc3 .. 3. f4...
Why is this considered much more solid/sound than just the King's gambit. It doesn't seem to me that the extra 2. Nc3 thrown in is doing anything?
Additionally, how is the Vienna gambit different from the Vienna game when 3. g3 is played? 3. g3 followed by fianchetto of the f1 Bishop seems to give more semi-open positions. So it seems to me that 3. f4 and 3. g3 would lead to very very different types of games and should be considered two different openings entirely.

The inclusion of 2. Nc3 ahead of f2-f4 is most significant.
Consider 1. e4 e5 2. f4. Does 2. f4 aid White's development? Does 2. f4 make a threat? In both cases, no. 1. e4 e5 2. f4 isn't a threat because if we gave White an additional move for 3. fxe5, then 3...Qh4+ ruins White's day. That's the first reason for 2. Nc3: by guarding e4, it means f2-f4 will make a genuine threat of f4xe5 because following ...Qd8-h4+, ...Qh4xe4 is out of the picture.
The other reason for 2. Nc3 is its influence on d5, given that when White plays f2-f4 as a means of getting the upper hand in the center (by deflecting the e5-pawn, or capturing it), Black's simplest counter in the center is ...d7-d5. However, it does not at dissuade Black from  2. Nc3 Nf6 3. f4 d5, by far the most common continuation.
If White wants to play this flavor of Vienna, he has to like the positions that result from 4. fxe5 Nxe4 5. Nf3. If White really wants to shut off ...d7-d5, he can postpone f2-f4 for still another move with 3. Bf1-c4. That invites the craziness of 3...Nxe4, which is a whole 'nother ballgame.
2...Nf6 3. f4 d5 is most common, but say Black lets White carry out his plan. Suppose 1. e4 e5 2. Nc3 Nc6 Then 3. f4 exf4 4. Nf3. Black is willing to go for this because the knight on c3 is sort of misplaced!
Again, consider the immediate 2. f4. 1. e4 e5 2. f4 exf4 3. Nf3
(3. Bc4 was the choice of Fischer and Polgar, allowing 3...Qh4+, for whatever that' worth. Keres played 3. Nc3 in his brash youth, after which 3...Qh4+ is more meaningful because White's flight is Ke1-e2 rather than Ke1-f1. Steinitz tried the most thematic 3. d4, but 3...Qh4+ compels 4. Ke2 in that case, also. I wrote an entire book on 3. h4.)
3...g5 4. Bc4
(4. h4 is more positionally logical, though 4. Bc4 is equally popular, partly because some players with Black will choose 4...g4 5. O-O gxf3)
4...Bg7.
4...Bg7 is a huge move, mostly because it guards the h8-rook,. so 5. h4 doesn't force ...g5-g4, but can be met by 5...h6 6. hxg5 hxg5 7. Rxh8 Bxh8.
And since ...Bf8-g7 is such a useful move for Black in those King's Gambit Accepted positions, White would rather leave c3 open for the pawn to support d4 (but that Vienna knight prohibits that, and is therefore somewhat misplaced — how ironic).
About 1. e4 e5 2. Nc3 plus 3. g3. There White is keeping f2-f4 in reserve for a long time, after his kingside development is complete (the Bg2 influences Black's main counterattack square d5 from a distance), and the queenside has d2-d3, after which f2-f4 will have the Bc1 behind it and the  Pg3. These positions are actually very quiet because the pieces don't come into contact as quickly (obviously g2-g3 plus Bf1-g2 is less combative than Bf1-c4 which invites a fight with ...Ng8-f6 plus ...d7-d5). In many of those games, White kept f2-f4 in reserve until it most safe, and then goes on with f4-f5 to take all the kingside space (presumably while Pe4, Nc3, and Bg2 keep Black under wraps).


Bishop's opening - avoiding positional lines as Black after 2...Nf6 3. d3 I'm currently experimenting 1...e5 against 1.e4 aiming at the Petrov but I sometimes encounter Bishop's opening 2. Fc4 to which I reply 2...Nf6.

If White play 3. Nc3, I have some ideas, but if they play 3.d3, it's another story since after 3...Nc6, White can play 4.Nf3 that leads to a positional Two Knight's.
And playing 3...Bc5 leads to a Guoco Pianissimo which I want to avoid at all cost.

Are there some interesting lines here for Black considering the above ? Even if it's slighty inferior. Thanks

rnbqkb1r/pppp1ppp/5n2/4p3/2B1P3/3P4/PPP2PPP/RNBQK1NR b KQkq - 0 3

3...c6 is in my opinion by far the best move here. Usually white would continue with something like 4.Nf3 Be7 5.O-O (5.Nxe5 Qa5+) d6. 5...d6 is a more solid choice but 5...d5 is another option if you want to blast open the center quicker. For a nice game with 5...d6 played, take a careful look through Gelfand - Yusupov, Munich 1994.


What's wrong with 4...e5 in the Open Sicilian? I like to play 4...e5 in the Open Sicilian in my games, usually facing something like this:

[StartPly "8"]

[fen ""]
1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 e5 5. Nb3 Nc6

I do this to:

Chase the knight so that it doesn't block advancing my pieces.
Regain control of the center after 3...cxd4.
Gain a tempo.

Is there any disadvantage in doing this ?

After 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 e5 5.Nb3 Nc6, the position is probably fine for black.

However, after 4....e5, white seems to have a stronger reply: 5.Bb5+. According to the Game Database of ChessTempo, this is also the most popular move. Now, black has two options: 4....Bd7 or 4....Nd7. After both moves, white can put his knight on f5 and obtain a slightly better position.

Therefore, I would say that 4....e5 is a small inaccuracy. However, the ideas behind the move (occupying the center, gaining a tempo) are perfectly fine.

Maybe it is interesting to take a look at:

the Sveshnikov variation: 1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 e5
the Kalashnikov variation: 1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 e5
the Classical variation: 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 Nc6, and after 6.Be2, 6....e5
the Najdorf variation: 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6, and after 6.Be2, 6....e5

      [FEN ""]
      [StartPly "3"]

      1.e4 c5 2.Nf3 d6 (2...Nc6 3.d4 cxd4 4.Nxd4 Nf6 (4...e5) 5.Nc3 e5) 3.d4 cxd4 4.Nxd4 e5 (4...Nf6 5.Nc3 a6 (5...Nc6 6.Be2 e5) 6.Be2 e5) 5.Bb5+ (5.Nb3 Nc6) 5...Nd7 (5...Bd7 6.Bxd7+ Qxd7 7.Nf5) 6.Nf5


High-quality (not bitmap) diagram software I'm looking for software that can take FEN and generate a high-quality diagram, in PDF, Postscript, Windows metafile, or something else that will look good at 1200x1200 dpi or better. I thought the various chess engines would do it, but their diagrams are all bitmaps (as far as I can tell) and look like garbage when resized arbitrarily. Also, their own publishing export can’t be edited in anything standard, AFAICT. I am willing to pay.

As thb pointed out, you need vectors. I suggest you use a python-chess to generate SVG vector images.

Prerequisites:

Python 2.6+ or 3.3+
Python-chess:

Install form pypi using pip: pip install python-chess[uci,gaviota]

Creating a script

Since you might need to generate multiple SVGs, let's create a script.  So, you can use the script to generate multiple chess boards easily. The following is written in Python 3.x. Create a Python script, FENtoSVG.py for example. Insert the following code:

import chess, sys
from chess import svg
'''
This imports python-chess module and sys module.
Python-chess will generate the boards while sys.argv will take
arguments for your script.
'''
svgstomake = (list(sys.argv))[1:]
for svgs in svgstomake:
    board = chess.Board(svgs)
    nameoffile = svgs.replace("/", "")+".SVG"
    boardsvg = chess.svg.board(board = board)
    filetowriteto = open(nameoffile, "w")
    filetowriteto.write(boardsvg)
    filetowriteto.close()

If you are on linux, start script with #!/usr/bin/env python3.

Usage

Now, this is a very simple script if you know python but I want to keep it simple for those who don't code. To use the script, open CMD/Terminal where you saved the script. Then, use as follows:

./FENtoSVG.py "examplefen" "morefen"

Say I want two SVGs for the FEN "8/8/8/8/4N3/8/8/8 w - - 0 1" and "8/8/8/8/4Q3/8/8/8 w - - 0 1"
, I would enter:

./FENtoSVG.py "8/8/8/8/4N3/8/8/8 w - - 0 1" "8/8/8/8/4Q3/8/8/8 w - - 0 1"

This would create two files: 88884N3888 w - - 0 1.SVG and 88884Q3888 w - - 0 1.SVG

I suggest python-chess because of the customizations that can be easily made to the diagram using built-in functions. It is also well documented.


How does Magnus create opportunities for his opponents to go wrong? I have heard this statement many times, but I don't understand it. What does it mean exactly?

An interesting question!
I think it was Kramnik who, when asked who the best player on earth was, mentioned some other player. When asked why not Carlsen he replied: Magnus is from another planet!
That such a great player as Kramnik, conquereor of Kasparov, was in awe of Carlsen speaks volumes.
His "sight of the board" is phenomenal as is his ability to detect tactical possibilities.
How does he create opportunities for his opponents to go wrong?
The simple answer is by continuing to play!
He seems to absolutely love playing chess and plays out positions that many other GM's would pass up as too dry and drawish.
He has a superb ability to find resources in any position where other GM's cannot. Sometimes the advantages are only microscopic but Carlsen is willing to steadily seek out and accumulate these and convert drawish positions into winning ones.
Carlsen seems content to just get a playable position out of the opening rather than dominate with superior opening knowledge like Kasparov could do.
If you play through his games he often switches play back and forth from the centre then to one wing then to the other. He keeps sustained pressure on his opponent and squeezes as much as possible out of any position.


What makes a contemporary chess problem decent? One can set up some pieces and concoct a situation that has, say, a mate in 3 (yes, I know it is not straightforward, but if you sit for a few hours you can do it).

Such problem would probably not be accepted for a competition because the modern standards are already too high. There has to be a relatively original idea and/or theme, but I do not know what qualifies as mediocre these days, and what qualifies as novel.

One might simply look at the judging metrics at the World Chess Composition Tournament (WCCT) to derive such an answer.

This is from their Rules Annex and details how points are allocated to a composition entry. I've stressed key words that probably represent a figure of merit.

  Points : Description

  4.0 : An outstanding problem: an accurate and intensive rendering of the set theme, without blemishes in any of the main lines, and showing
  originality and flair. Perfect construction and economy.

  3.5 : As above, but some small constructional weaknesses, and perhaps not ideally economical.

  3.0 : Either: a very good problem showing the theme clearly but perhaps not intensively or very originally Or: a task rendering of the theme
  which does not reach the highest artistic standard. In either case,
  good construction and economy.

  2.5 : As above, but constructional weakness and/or less than ideal economy because of the intensive or task setting.

  2.0 : A good problem, very likely worth an honourable mention or commendation in a reasonably strong tourney, but not a very intensive
  rendering of the theme, and perhaps not very original. Adequate to
  good construction and economy.

  1.5 : As above, but with some artistic weakness or constructional blemish.

  1.0 : A very ordinary piece of work, typical of many average columns but hardly up to award standard. Adequate construction and economy.

  0.5 : As above, but with serious constructional defects.

  0.0 : Unsound, unthematic or fully anticipated.


Is it good to take a fianchettoed Bishop? I have faced this fairly often in quite a few openings, but there seems to be a theme with players putting their Bishop on a square like h6, supported by a queen and attacking the fianchettoed Bishop next to the castled King.
What are the ideas behind this? Is it something I should be bringing into my own gameplan and if so is taking the fianchettoed Bishop a good thing to do? It seems to me to be the only point in putting it there.

There are two reasons for doing this and immediately taking the fianchettoed bishop is not one of them:

Provoke Black into playing BxB when you hope to follow up with Ng5, drive the f6 knight away and then mate on h7
Prevent black from playing h5 until you have been able to play h2-4-5 to pry open the
black king's position.

It can even be worth sacrificing the exchange with h5, Nxh5 Rxh5 to smash open the black citadel.


The London 2018 World Chess Championship live coverage sources Which TV channels are going to stream the WCC? Preferably with English commentary. (With live video from the playing board, not only the moves).

I believe the live video footage is restricted to the official broadcast and you probably have to pay to get access to it.
The footage aside, the games will be broadcasted live on chess24 for free (even without an account) with a phenomenal team of commentators, namely, Peter Svidler, Sopiko Guramishvili, Alexander Grischuk, Anish Giri for the English commentary and there will also be separate commentaries in Spanish and German covering each round.

Here's their dedicated page to the WCC2018: https://chess24.com/en/wcc2018
And the featured page (including engine analysis etc): https://chess24.com/en/watch/live-tournaments/carlsen-caruana-world-chess-championship-2018/1/1/1


Can a player move before his opponent hits the clock? In a reply to another question, I made an explicit presumption that under FIDE Laws, a player can move as soon as the opponent’s move has been made. But someone wondered if this was this really correct.

The Laws make a distinction between a move being ‘made’ and a move being ‘completed’ (when the clock has been hit). As far as I can tell, the former (under which the waiting player is said to ‘have the move’) is sufficient for allowing the next player to move. But there is no rule which says you can move when you have the move, maybe because it’s deemed too obvious.

As far as I can see the following scenarios are legitimate:

A: move
B: move
B: hit clock but nothing happens
A: hit clock
B: hit clock

A: move
B: move
A: move
A: hit clock
B: move
B: hit clock

And might as well list a related scenario:

A: move
B: wait for A to realise
A: hit clock

But I am not an arbiter. Can a player move before their opponent hits the clock?

There is no requirement to wait until the opponent has pressed the clock before making your move. However issues can arise with getting the increment to which the player is entitled for every move made if the clock is not pressed and this is spelled out in the FIDE Laws of Chess:

  6.2.1 During the game each player, having made his move on the chessboard, shall stop his own clock and start his opponent’s clock
  (that is to say, he shall press his clock). This “completes” the move.
  A move is also completed if:

  6.2.1.1   the move ends the game (see Articles 5.1.1, 5.2.1, 5.2.2, 9.6.1 and 9.6.2), or

  6.2.1.2 the player has made his next move, when his previous move was not completed.

  6.2.2 A player must be allowed to stop his clock after making his move, even after the opponent has made his next move. The time between
  making the move on the chessboard and pressing the clock is regarded
  as part of the time allotted to the player.

From 6.2.1.2 it is clear that is fine for player B to make his move before player A has pressed the clock to complete his previous move.

From 6.2.2 it is clear that in that case player A is entitled to press the clock for that move even after player B has made a quick move.

The act of pressing the clock fulfils two functions:

It "completes" the move. This is important because an illegal move is
not punishable and can be retracted without penalty if the move
hasn't been completed.
It is the action which gives the player the increment to which he is entitled.


Chess engine with no evaluation One of the most difficult parts of a chess engine is the evaluation function. Handcrafted evaluation functions are very long and complicated, while NN evaluations are hard to make and train. That's why I was wondering whether an implementation of a chess engine with no evaluation function would be possible. Search algorithms like MCTS don't need an explicit one, as they can rely on random playouts.
Could a similar approach be used to create a chess engine with a random search algorithm, which averages the results from those random games and optimally reach to the best move?
Theoretically, it should converge to the optimal solution (minimax), right?
Of course it would be for testing and experimentation purposes, but I think with a good implementation of the algorithm, it should play at least at almost master level. I would implement it on Golang, as it would be easier to implement concurrency/parallelism.
What are your thoughts on this?

I have tried using MCTS before for a chess engine and the results were not very good. The problem was that the results when playing out a game with only random moves were basically just that: random. Most of the results would only be reached after over 100 plies so the initial position had little to do with the result.
I had better results when I cutoff the tree after x plies where x would be somewhere between 20 and 50 and using a simple evaluation function for that position. But then you would be relying on a evaluation function again.


Why isn't Chess960 the standard? Bobby Fischer said that standard chess is dead and I believe him. Current players rely too much on engine-moves and theory in the openings and quite far in the middle-game without any real calculations, but memory. For instance, Carlsen had memorized engine-moves far into the middle game against GM Sergej Karjakin when playing white, which I find unfair.
Chess960 allows for 960 different positions to begin the game and no GM would be able to analyze every start to the current extent. Thus, Chess960 would rely on raw talent and calculations. Why isn't it the standard nowadays?

Chess players identify with their openings, all chess clubs have that one guy who always plays stodgy London stuff with white, the maverick with all his dodgy gambits and the youth player with 25 moves of Najdorf theory memorized for the day he finally gets to play it.

Opening books are by far the most sold type of chess book, and the number of titles is much larger than that of other types of book. People write hundreds of pages of grandmaster level analysis on a line that starts on move 6 and still lots of amateurs buy the books.

When an amateur watches a grandmaster game live, he uses knowledge of the opening played to understand what is going on. If they play a King's Indian and the center is locked, one of them is going to attack on one wing and vice versa. If it's a closed Ruy Lopez, we know there's probably a slow maneuvering game coming up, et cetera.

Playing memorized opening theory gives the amateur the feeling that for that part of the game at least, he is playing at grandmaster level.

In other words, chess players like opening theory.


Should I join a chess club? I started playing chess around 1 year ago, all I have done is watch some videos and play online, so my knowledge is pretty poor. I am coming to a new city and I was thinking about joining a chess club, although given my level I am a bit ashamed of doing so. I wrote them and they told me the club is pretty strong, but I can go and give it a try anyway, which only scared me more.

Since I have never played anyone with a fide rating I really don't know my strength, so I was wondering if pasting a game here would allow someone with a deeper knowledge to make a (very) rough estimation:

[FEN ""]
1. e4 c5 2. Bc4  e6 3. Nc3 Ne7 4. f4 d5 5. exd5 exd5 6. Bb5+ Bd7 7.    Bxd7+ Qxd7 8. Nf3 Nbc6 9. O-O g6 10. d3 Bg7 11. Re1 O-O 12. Bd2 Nf5 13. Ng5 Ncd4 14. Rc1 Nh4 15. Rf1 Rae8 16. g3 Nhf5 17. Qg4 b5 18. Rfe1 Rxe1+ 19. Bxe1 Re8 20. Bf2 b4 21. Bxd4 Bxd4+

That's the game I just played (I'm black), for some reason I don't have an account on a website yet so the rest are not saved. Although I must admit I am very proud of that one, so maybe is not very representative (I can play more games and post them later if necessary). I just want a bunch of opinions so I can get an idea if I am close to the "club level".

P.D. The chess club is called Sk1968, in case someone knows how to check the members, so far I have not managed to do it.

You should try it. Over the board chess is a very different experience, the social aspect is a lot of fun and the level of concentration required very different from online. Also there is no better way to improve your chess than discussing a game with your opponent afterwards.

It appears you're talking about "Skakklubben 1968" in Århus, Denmark. It appears to have about 100 members! They probably have quite a few people showing up for their club evenings, which is fun and it means they're likely to have a lot of different skill levels playing.

Danish ratings (not FIDE, but I suppose similar) can be found on www.skak.dk; in particular, for this club at this page. That's a very strong club indeed, with ten 2200+ players! But the bottom are around 1000-1200 or so, so that's OK.

But, in general, when starting at a chess club as an adult you may well have a hard time. Some people lose everything their first year! From playing online, you're not used to the kind of people who don't attack much, don't play opening theory much, don't know much about positional play try to stay solid, but grab their chance when you drop a pawn to a small combination and then just exchange everything and win with it. Stick with it, it's worth it! You'll eventually beat them easily if you just keep improving.


Is a rook ending where the winning side has a passed g and d pawns drawn? The passed pawns are g and d pawns. Can the losing side draw such a rook endgame? Can you give some examples to how or why it can't be drawn?

By definition if there's a "winning side" and a "losing side" then
the question is already answered :-)

But seriously, if you just want K+R+P(d)+P(g) vs. K+R, that's within
database range, so you can explore for yourself
here.
In general such positions are easy wins (note that the defending
King can "always" be cut off from one pawn or the other by a
Rook move to e or f), though naturally there are some initial positions
where one pawn is lost tactically to leave a draw, and there can even
be "accidents" such as this:

6r1/8/7k/8/3P1KP1/8/8/4R3 w - - 0 0

1. Kf5?? Rf8+ 0-1


Combining AlphaZero methods with Stockfish methods NOTE: I asked a similar question at the ai stackexchange, but didn't get any satisfying answers, so I will post an updated version of the question here, to see if someone with more of a chess background can answer it.

In short terms: Is it possible to combine the techniques used by AlphaZero with those used by, say, Stockfish? In AI terms that would be combining deep reinforcement learning with alpha-beta pruning. And if so, has it been attempted?

I have only a brief knowledge about how AlphaZero works, but from what I've understood, it basically takes the board state as input to a neural net, possibly combined with monte carlo methods, and outputs a board evaluation or prefered move. To me, this really resembles the heuristic function used by traditional chess engines like stockfish.

So, from this I will conclude (correct me if I'm wrong) that AlphaZero evaluates the current position, but uses a very powerful heuristic. Stockfish on the other hand searches through lots of positions from the current one first, and then uses a less powerful heuristic when a certain depth is reached.

Is it therefore possible to combine these approaches by first using alpha-beta pruning, and then using AlphaZero as some kind of heuristic when the max depth is reached? To me it seems like this would be better than just evaluating the current position like (I think) AlphaZero does. Will it take too much time to evaluate? Or is it something I have misunderstood? If it's possible, has anyone attempted it?

---Reopening motivation---

This closed question may have a good answer in https://www.newinchess.com/komodo-chess-13

You are asking the right question but only want to refine your premise slightly. AlphaZero does indeed search "through lots of positions from the current one first," as you have said, only not precisely via alpha-beta pruning. AlphaZero's makers explain it thus:

  Instead of an alpha-beta search with domain-specific enhancements, AlphaZero uses a general-purpose Monte Carlo tree search (MCTS) algorithm. Each search consists of a series of simulated games of self-play that traverse a tree from root state s root until a leaf state is reached. Each simulation proceeds by selecting in each state s a move a with low visit count (not previously frequently explored), high move probability and high value (averaged over the leaf states of simulations that selected a from s) according to the current neural network fθ. The search returns a vector π representing a probability distribution over moves, πa = Pr(a|sroot).

As you know, most opening and middlegame positions make it impractical to search all relevant chessboard futures, so the question is how to prune the search tree. AlphaZero prunes the tree as explained but, for each relevant chessboard future not pruned, evaluates the position by neural net.

Thus, contrary to your premise (if I grasp your premise correctly), AlphaZero judges not only the position actually on the board but also potential future positions.

If you have had occasion to review Stockfish's source code you will have noticed how straightforward Stockfish's evaluation function is. It's fairly simple and very quick. The speed of AlphaZero's evaluation function naturally depends in part on the hardware on which AlphaZero is run but in the absence of exotic hardware AlphaZero's evaluation can hardly be as fast as Stockfish's. Therefore, significantly, as far as I know, Stockfish has the advantage of evaluating more chessboard futures than AlphaZero can. Your premise is right to that extent.

Nevertheless, AlphaZero

searches more chessboard futures than a human master can, and
apparently evaluates each better than Stockfish can.

This is reportedly how AlphaZero plays better than either.

Insofar as AlphaZero's makers have not released their source, it is hard to say too much more, but meanwhile you may have heard of LCZero, a vigorous open-source attempt to replicate AlphaZero's results. If you have not heard of LCZero, also known as "Leela," then you might investigate when you have some time.


Unclear endgame / late middlegame position: looks like advantage white to me, but engine analysis suggests draw Came across this position as part of some variation analysis of one of my previous games. To me it looks like a noticeable (though probably not decisive) advantage for white -- based on pawn structure and bishop over knight.  Engine analysis however (Stockfish) seems to suggest a draw.

Perhaps someone more knowledgeable than me could resolve my confusion here to a degree, by commenting either why the game isn't likely to be drawn (ie the engine is wrong), or why I'm wrong in seeing an advantage for white when there is none.

8/1pk2p2/p2p1n2/2pPbP2/P1P5/1P2K3/4B3/4B3 w - - 87 88

It is true that White has a slight material advantage (the bishop pair vs bishop and a knight), but White's light-squares' bishop is confined to your side of the board and cannot attack any of Black's pieces.  White's dark-squares' bishop cannot enter Black's territory or attack any of Black's pieces either, and your king has a long way to go to attack Black's isolated pawn on f7.  Black's king can easily defend their isolated pawn and Black can further close the position with b7 (so White's dark-squares' bishop cannot attack Black's pawn on d6 from c7 or b8 and overload Black's king while it is defending Black's pawn on f7).  It seems similarly difficult for Black to make any real progress towards a win, so in my inexpert assessment a draw is likely.


What was one shortcoming of alpha zero that Kasparov noted? I [Kasparov]  can look at AlphaZero’s games and understand the
  potential weaknesses. And I believe it has made some inaccurate
  evaluations, which is natural.

The reason he says that is AlphaZero uses statistics of ALL games to determine piece value.

Which pieces did he specifically mention?

What other shortcomings does alpha zero have that humans could exploit?

First, as great as Kasparov is, compared to AlphaZero, even he is a patzer; so for him to say that he sees weaknesses, he may be correct, but it could also be, simply, that AlphaZero is playing at a level beyond even his great understanding, and with positional/tactical minutia we, humans, have yet to realize are important, or cannot see at all.

In this interview, he only mentioned bishops versus knights, saying:

  I can look at AlphaZero’s games and understand the potential
  weaknesses. And I believe it has made some inaccurate evaluations,
  which is natural. For example, it values bishop over knight. It sees
  over 60 million games that statistically, you know, the bishop was
  dominant in many more games. So I think it added too much advantage to
  bishop in terms of numbers. So what you should do, you should try to
  get your engine to a position where AlphaZero will make inevitable
  mistakes [based on this inaccuracy].

Note: I believe the 60 million games he mentions are all games played against itself as it was teaching itself how to play, rather than a database of human games. After all, Mega 2020, has only 8 million games in it.

I also found this article that Kasparov penned, in which he said:

  But in my observation, AlphaZero prioritizes piece activity over
  material, preferring positions that to my eye looked risky and
  aggressive.

Considering the recent question, "Is Stockfish 11 (level 20) beatable?", and that AlphaZero destroyed a recent, although previous, version of Stockfish, I do not believe that you will find any weaknesses that any human will be able to exploit. That will be the domain of the next, stronger, computer.


Did Stockfish have access to an opening book in its games against AlphaZero? I have seen some commentary that implies that Stockfish did not have access to an opening book in its much-reported match with AlphaZero, but I cannot find a conclusive citation, and my inability to do so has me wondering if maybe Stockfish did have an opening book after all.

For example:

  GM Hikaru Nakamura...called the match "dishonest" and pointed out that
  Stockfish's methodology requires it to have an openings book for
  optimal performance. While he doesn't think the ultimate winner would
  have changed, Nakamura thought the size of the winning score would be
  mitigated.

or, from a StackExchange answer:

  Stockfish...wasn't allowed to use an opening book which makes it
  consider many moves in shallow depths.

It's worth noting that even if Stockfish didn't have an opening book for the canonical 100 game match, page 6 of the paper shows that AlphaZero is dominant when you start from a variety of common openings. Nonetheless I wonder why they would handicap Stockfish this way.

Both Nakamura and the StackExchange answer were correct - Stockfish didn't use an opening book. I think Google did that to make a fair comparison as AlphaZero wasn't using an opening book as well.
EDIT
I didn't see anything about opening book for Stockfish in the paper. I'm not the only one.

http://talkchess.com/forum/viewtopic.php?t=65910&postdays=0&postorder=asc&highlight=stockfish+book&topic_view=flat&start=10
As far as I read the paper, I didn't see a book for Stockfish mentioned, so I guess, match was bookless.

and

http://talkchess.com/forum/viewtopic.php?t=65909&highlight=stockfish+book
While this is indeed incredible, show me how it beats SF dev with good book and syzygy on equal hardware in a 1000 game match.


Why is the latest Stockfish (2.2.2) infinitely slower (than 2.1.1) in Scid? I was about to spend some time researching this, but realized someone might have already looked into it; if not, I may just answer my own question in a few hours.

Scid is pegging one core of the CPU, possibly trying to keep up with input from Stockfish? Stockfish is using 0% CPU, possibly blocking while piping output to Scid. That is just what I suspect is happening--haven't confirmed. In any case, stockfish takes a minute or two to get to 2 depth in analysis--usually after a few seconds I'm to 15 depth at least, so it's orders of magnitude slower.

I didn't change any of my UCI settings, just simply upgraded the executable. Same thing happens on Mac and Windows, so it's probably not platform specific, but something related to the UCI interface?

I have hash size set to 1024MB, "use sleeping threads" = true, and multiple variations set quite high (100 or so), to see all variations scored and searched, which helps in analysis even though it slows down the depth search. The rest of the settings are default (I'm fairly certain).

So, I hashed this out some in a support thread on the stockfish forum.

Basically, you should skip 2.2.2 and compile the latest from github (or just continue to use 2.1.1). I think I'll try this new code for a while to see how it does. The latest code from github works great in chesstempo's UCI connector. It's still a little slow out of the gates in Scid (and Scid acts like it's hanging and doesn't respond to UI commands), but it speeds up as it gets deeper in the search, so it's bearable after 30 seconds or so. I had trouble getting multipv (multiple variations) to work at high numbers, though.

I think Scid should not block the input from the UCI interface--buffering more, if need be. Maybe I'll take a look at the Scid code later to see if I can improve it.