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Horizon Effect

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How long do top chessplayers calculate?. Non players believe that the best chesslayers are  able to calculate many many moves in advance. This is but a “cliché”  (in the same way that many people believe that if you, a chessplayer, plays against a less-skilled or ocassional opponent you have to win in a few moves…).

Steinitz declared that the matter depended on the level of his rival. Kasparov said that in positions with forced lines he could calculate around ten even fifteen moves. In other cases -complicated positions- he said that one has to rely upon his/her intuition + the positional understanding and in these case perhaps only from 5 to seven moves can be calculated. Some experts warn of the famous “two move principle” (the name is mine).

Well, the mind of a professional does not work so strictly  (I mean they do not care about these “scholastical” matters…) .They have a position in front of them and , generally speaking, know the plans associated to the opening played. Then,  in an unconscious way, they begin to apply their knowledge of the position, the pattern recognition, their intuition, their ability to perceive immediate tactical nuances , their strategical knowledge and their positional insight. They are able to use a sort of goal-oriented thinking to take advantage of the assets or to determine that the opponent’s threats are more dangerous than his own and consequently he has to define a plan of defence.

The term “horizon effect” appears related to artificial intelligence. In short: when evaluating possible future positions and decide where to stop the calculation, what would happen if the engine stops on move 10 and on move 11th there is a mate in one?. This tries to be avoided introducing what is known as “quiescence search”.

In OTB Chess there are hundreds of  examples where both players reach an opening position where both parties believe the advantage is on their respective sides. The ensuing play and the post-mortem analysis will prove who was right. In other cases  one of the players has a better vision, calculates one step ahead ad is able to beat his opponent who had stopped calculating one or more steps behind his rival.

Chess is  very complicated, with many absolutely different factors intervening (even top GMs and World Champions have been defeated in less than 20 moves, for instance).

Abrahams wrote that “the very best players very rarely make any perceptible tactical error. They lose by choosing a bad strategical line and persisting in it. They lose, in effect, by trying to do too much (or too little).” .- “The Chess Mind”  (Of course all this under normal circumstances I add).

Kotov wrote that you could find that some leading players might overlook a combination, but that you would never find one who calculated variations badly.

W.: E. Geller (1)

B.: Y. Anikaev (o)

Minks 1979

1. e4 c5  2. Nf3 e6  3. d4 cd4  4. Nd4: Nf6  5. Nc3 d6  6. Be2 Be7  7. 0-0 0-0  8. f4 Nc6  9. Be3 a6  10. a4 Bd7  11. Bf3 Na5  12. Qe2  Qc7  13. g4 Rfc8  14. g5 Ne8  15. f5 Nc4  16. Bh5 g6  17. fg6  fg6  18. Qf2! Ne5  19. Nf3!  Ng7  20. Ne5: Rf8  21. Nf7! Nh5:  22. Nd5!! ed5  23. Nh6 Kg7 24. Qf7! Rf7:: 25. Rf7: Kh8  26. Bd4 Bf6  27. Rf6!  and Black resigned.  What a thrashing!

W.: L. Portisch (0)

B.: J. Pinter (1)

Hungarian Chess Championship 1984

1. d4 Nf6  2.c4 e6  3. Nf3 d5  4. Nc3 c5  5. cd5 Nd5:  6. e4 Nc3:  7. bc3 cd4  8. cd4 Nc6  9. Bc4 b5 10. Be2 Bb4  11. Bd2 Qa5  12. Bb4: Qb4:  13. Qd2 Bb7  14. a3 Qd2: 15. Kd2: a6  16. a4 b4  17. a5?! Rd8  18. Ke3 f5!  19. ef5 ef5  20. Bc4 Ke7  21. d5  Kf6!  22. dc6 Rhe8  23. Kf4 Re4  24. Kg3 Bc8!  25. Rac1  Rg4  26. Kh3  f4  27 Ne5? (The losing move. It was necessary 27 Ba5:) 27. … , Kg5  28. Nf7  Kh5  29.Be2 Rd3  30. g3  f3  31. Rc5  Rg5  32. g4  Bg4:  33. Kg3  fe2  and White resigned.


Written by QChess

May 8, 2012 at 7:28 am

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