| Jul-07-02 | | refutor: nice combination by korchnoi |
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| Jul-07-02 | | morphynoman: Nice game, really! |
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| Jan-06-18 | | Mikhail1962: Very nice game. |
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| Apr-05-21 | | Gaito: This game is game number 4 in the book "Korchnoi's 400 Best games" by Viktor Korchnoi. |
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| Apr-05-21 | | Gaito: 
click for larger view BLACK TO MOVE
This is a theoretical position that has been repeated hundreds or thousands of times in master play: the so-called "Anti meran D44" or "Botvinnik System", a line almost as complicated and thoroughly analyzed as the Najdorf Poisoned Pawn. What is Black's best move in this position? It is hard to say. The main line (or "book move") is 11...Qa5, as played by Korchnoi in this game. In 1945 this position was apparently played for the first time in a game Denker vs. Botvinnik, radio match USA vs. USSR. Botvinnik played 11...Bb7 which, incidentally, is the move chosen by modern chess engines like Stockfish 13 and LcZero. After 11...Bb7 Arnold Denker played 12.Be2? which, according to Korchnoi is a not a good move. You can see that game in this link:
Denker vs Botvinnik, 1945 |
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| Apr-05-21 | | Gaito: After 11...Bb7 (instead of 11...Qa5), White should probably develop his his KB by fianchetto, i.e. 12.g3. This is, at least, the move chosen by the chess engines SF13 and LcZero. For example: 11...Bb7 12.g3 c5 13.d5! Another possibility after 11...Bb7 is 12.h4!? |
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| Apr-05-21 | | Gaito: After 11...Qa5, White's best move is 12.g3⩲, as played by Lev Aronson in this game. (This is also the move chosen by modern computer engines). Another possible move is 12.Be2. An excellent game played in the US championship, 2007 between Onischuk and Shabalov continued with 12.Be2 Bb7 13.O-O O-O-O. You can see that game in the following link:
Onischuk vs Shabalov, 2007
That game was selected as one of the 10 best games in Chess Informant number 100. |
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Apr-05-21
 | | Honza Cervenka: 12.g3 is a deep theory now. See Opening Explorer |
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| Apr-05-21 | | Gaito: 14.Be2 is a good (theoretical) move, but also 14.Qf3 deserves attention. White is supposed to have a slight plus (⩲) after either of those moves. |
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| Apr-05-21 | | Gaito: <Honza Cervenka: 12.g3 is a deep theory now. See Opening Explorer> Thanks for that remark. Good to know that. |
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Apr-05-21
| | Honza Cervenka: 14.b3 is also playable here. |
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| Apr-05-21 | | Gaito: 
click for larger view BLACK TO MOVE
What is Black's best move in this position? I am far from being an expert on the Botvinnik Anti Meran System, but I would suspect that 14...O-O-O could be the "book move". Incidentally, engine LcZero likes 14...O-O-O. However, in his book ("400 Best games") Korchnoi wrote that his move 14...Qf5! was an improvement over 14...O-O-O, as played for the first time in a game between Baturin and Ravinsky, USSR, 1946. That game unfortunately can't be found in this site or in Internet as far as I know. But Korchnoi mentioned that it went as follows: 14...O-O-O 15.O-O Qf5 16.f3? Nc5 17.Nxc5 Rxd4! (− +) (Diagram below):
click for larger viewWHITE TO MOVE
Position from the game Baturin vs. Ravinsky, USSR, 1946. If now 18.Qxd4?? Bxc5 wins the queen. The rest of that game is apparently unknown. But it is clear that White is busted. |
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| Apr-05-21 | | Gaito: 
click for larger viewBLACK TO MOVE
30...Rd3!! 31.Kb5 (if 31.b3 Rf3 32.Bxa7 Rxf6 wins for Black, according to Korchnoi in his comments from the book "400 Best Games") |
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| Apr-06-21 | | Gaito: The critical moment of the game (or the inflection point, as it were) must have been after Black played 14...Qf5 (Korchnoi attached an exclamation mark to that move in his book "400 Best Games"):
click for larger view WHITE TO MOVE
The position is favorable for White (±) with a numerical evaluation of +1.36 by Lc0, and +2.29 by SF13, which means that from the point of view of SF13 White has a clearly better position, almost a winning position. But since White lost the game, then it is reasonable to try to find out where he went astray. It seems that it was in this position that White made a mistake by playing 15.Qc2? The engines unanimously recommend the move 15.f3! (±) |
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| Apr-06-21 | | Gaito: Nevertheless, the move 15.Qc2 was probably not a real "mistake" but just an inaccuracy, because White still kept the upper hand even after that move (though the evaluation was lower), at least from the viewpoint of the chess engines. As a matter of fact, the critical position of the game was after 16...Bb7. Diagram below: 
click for larger view
WHITE TO MOVE
In this critical position, White missed a very strong move, namely 17.d5!! This is the sort of move that might be difficult to find for a normal human being (unless your name happens to be Bronstein). And after all, it is very logical to try and open up the position in the centre with the opponent's king still uncastled, in order to exploit one's superior development, something that is known since the old days of Paul Morphy. A couple of sample variations:
I) 17.d5!! Bxd5? 18.Nd6+! Bxd6 19.Qxf5 exf5 20.Rxd5 Bc7 21.Bxc4 (+ −), and White has a winning position II) 17.d5!! b3! 18.axb3 cxb3 19.Qb1 O-O-O (19...c4!? is worthy of consideration) 19.h4! (±) and White has a clear plus. Instead of the strong shot 17.d5!!, Aronson blundered with 17.Nxc5?, and after the exchange of queens he winded up with an inferior ending. |
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| Apr-06-21 | | Gaito: Why is it that the evaluation of a chess position by a human grandmaster sometimes is quite different from the evaluation made by a chess engine? Well, it could happen that the grandmaster is perhaps seeing something that the computer might be overlooking. That would be an exceptional case; but most of the time it is the other way around: the grandmaster might be overlooking something that the computer clearly sees. That was what happened in the following position:
click for larger view BLACK TO MOVE
Korchnoi played 15...c5!, which is possibly Black's best move in this position, and evaluated the position as clearly favorable for Black (∓). However, all strong chess engines disagree and consider the position after 15...c5 to be clearly better for White (±). How can we explain that disagreement? Well, it happened that Korchnoi was overlooking something that the computer clearly sees, namely that after 16.O-O-O Bb7 (16...b3!? is interesting but apparently no better), White has the strong breakthrough 17.d5!!, as analyzed above. It is possible that both players overlooked that strong move, and that might account for Korchnoi's belief that Black stood better in the position of the diagram, when in reality it was the other way around. |
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Kibitzing
