Author: Robert Hyatt
Date: 13:33:08 09/18/01
Go up one level in this thread
On September 18, 2001 at 13:24:45, Uri Blass wrote: > >Note that I said that computers can safely evaluate +2 if they do not see a >positional advantage for the side with less pawns. > >Having a distant majority is a positional advantage. Not when hardly _any_ programs recognize it. > >I also think that Ed is right and today search solves usually the problem of >missevaluating pawn majority. I disagree. If you enter into a series of captures, you might burn all your search on the captures and have none left to see what the majority is going to do. So you take the first step, and then you are committed. And every move you make sees your score drop as you begin to sense the problem. By the time the forced trades are done, you realize you are lost, as a king and pawns ending can be searched incredibly deeply. > >Here is an example that I composed: > >New position >[D]6rk/1p6/8/8/p7/6R1/P4PPP/7K w - - 0 1 > >Analysis by Deep Fritz: > >1.Rxg8+! > +- (2.97) Depth: 1/2 00:00:00 >1.Rxg8+! Kxg8 > +- (5.63) Depth: 1/3 00:00:00 >1.Rxg8+ Kxg8 2.Kg1 > +- (5.63) Depth: 2/5 00:00:00 >1.Rxg8+ Kxg8 2.Kg1 Kf7 > +- (5.59) Depth: 3/5 00:00:00 >1.Rxg8+ Kxg8 2.Kg1 Kf7 3.Kf1 > +- (5.59) Depth: 4/6 00:00:00 >1.Rxg8+ Kxg8 2.Kg1 b5 3.Kf1 b4 > +- (5.53) Depth: 5/7 00:00:00 >1.Rxg8+ Kxg8 2.Kg1 b5 3.Kf1 b4 4.Ke2 > +- (5.69) Depth: 6/9 00:00:00 1kN >1.Rxg8+-- > +- (5.38) Depth: 7/11 00:00:00 5kN >1.Rxg8+-- Kxg8 2.Kg1 b5 3.Kf1 b4 4.Ke2 b3 > +- (4.41) Depth: 7/11 00:00:00 6kN >1.Rxg8+-- > +- (4.09) Depth: 8/11 00:00:00 12kN >1.Rxg8+-- Kxg8 2.Kg1 b5 3.Kf1 b4 4.Ke2 b3 5.axb3 > +- (3.09) Depth: 8/12 00:00:00 13kN >1.Rxg8+ Kxg8 2.Kg1 b5 3.Kf1 b4 4.Ke2 b3 5.axb3 a3 > +- (2.91) Depth: 9/12 00:00:00 29kN >1.Rxg8+ Kxg8 2.Kg1 b5 3.Kf1 b4 4.Ke2 b3 5.axb3 a3 6.Kd3 > +- (2.88) Depth: 10/13 00:00:00 75kN >1.Rxg8+-- > +- (2.56) Depth: 11/14 00:00:00 176kN >1.Rxg8+-- > +- (2.56) Depth: 11/16 00:00:00 178kN >1.Rxg8+-- > +- (2.25) Depth: 12/15 00:00:00 533kN >1.Rxg8+-- Kxg8 2.g4 b5 3.a3 b4 4.axb4 a3 5.Kg2 a2 6.h4 a1Q > -+ (-3.44) Depth: 12/20 00:00:01 573kN >1.Rh3+! > -+ (-3.41) Depth: 12/20 00:00:01 614kN >1.Rh3+! Kg7 2.g4 b5 3.Kg2 b4 4.Re3 Rb8 5.Re7+ Kf6 6.Ra7 Rg8 > +- (2.06) Depth: 12/25 00:00:16 8180kN >1.Ra3 b5 2.h4 Rf8 3.Kg1 Rf4 4.g3 Rg4 5.Kg2 > +- (2.16) Depth: 12/25 00:00:16 9188kN >1.Ra3 b5 2.h4 Rf8 3.Kg1 Rf4 4.g3 Rg4 5.Kg2 > +- (2.16) Depth: 12/25 00:00:16 9188kN >1.Ra3 b5 2.Kg1 Ra8 3.Kf1 b4 4.Rd3 Rb8 5.Rd4 a3 6.Rd3 Kg7 > +- (2.09) Depth: 13/25 00:00:21 13276kN, tb=1 > >(Blass, Tel-aviv 18.09.2001) > >Note that Crafty also has not the knowledge of pawn majority and need a small >search to avoid Rxg8+ > >New position >6rk/1p6/8/8/p7/6R1/P4PPP/7K w - - 0 1 > >Analysis by Crafty 18.10: > >1.Re3 > +- (2.47) Depth: 1/4 00:00:00 >1.Rxg8+ > +- (2.87) Depth: 1/4 00:00:00 >1.Rxg8+ Kxg8 2.a3 > +- (2.92) Depth: 1/4 00:00:00 >1.Rxg8+ Kxg8 2.a3 Kf7 > +- (2.62) Depth: 2/4 00:00:00 >1.Rxg8+ Kxg8 2.a3 Kf7 > +- (3.02) Depth: 3/7 00:00:00 >1.Rxg8+ Kxg8 2.a3 Kf7 3.h4 > +- (3.02) Depth: 3/7 00:00:00 >1.Rxg8+ Kxg8 2.a3 Kf7 3.h4 Ke6 > +- (2.82) Depth: 4/9 00:00:00 >1.Rxg8+ Kxg8 2.a3 Kf7 3.h4 Ke6 > +- (3.22) Depth: 5/10 00:00:00 >1.Rxg8+ Kxg8 2.h4 Kf7 3.g4 Ke6 4.a3 > +- (3.24) Depth: 5/10 00:00:00 >1.Rxg8+ Kxg8 2.h4 b5 3.g4 b4 4.f4 Kf7 > +- (3.12) Depth: 6/12 00:00:00 7kN >1.Rxg8+ Kxg8 2.Kg1 b5 3.Kf1 Kf7 4.Ke2 Ke6 5.a3 > +- (3.10) Depth: 7/14 00:00:00 17kN >1.Rxg8+ Kxg8 2.Kg1 b5 3.Kf1 b4 4.Ke2 b3 5.axb3 a3 > µ (-1.25) Depth: 8/16 00:00:00 49kN >1.Rh3+ > µ (-0.85) Depth: 8/16 00:00:00 55kN >1.Rh3+ Kg7 2.a3 Rf8 3.Rg3+ Kh6 4.Kg1 Rc8 5.f4 Rc1+ 6.Kf2 Rc2+ 7.Ke3 b6 > +- (2.39) Depth: 8/16 00:00:01 308kN >1.Rh3+ Kg7 2.a3 Kf6 3.Rh7 Re8 4.h4 Re2 5.Rxb7 Rxf2 6.g4 > +- (2.37) Depth: 9/19 00:00:03 1098kN >1.Ra3 Re8 2.g3 b5 3.Re3 Rxe3 4.fxe3 b4 5.h4 Kg7 > +- (2.40) Depth: 9/19 00:00:03 1241kN > >(Blass, Tel-aviv 18.09.2001) > >Uri
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