Author: Andrew Williams
Date: 10:20:07 02/20/99
Go up one level in this thread
On February 19, 1999 at 14:03:03, Laurence Chen wrote: >GNUChess - PostModernist >r1bqr1k1/1p2bppp/2p1p3/p4n2/1P1P1BP1/2PB1N2/P4P1P/R2QR1K1 b - g3 0 1 > >Analysis by Junior 5.0: > >= (-0.12): 15...Nh4 16.b5 cxb5 17.Nxh4 Bxh4 18.Bxb5 Bd7 19.Rb1 Bxb5 20.Rxb5 Qf6 >21.Qf3 >= (0.11): 15...Bd6 16.Ne5 Bxe5 17.Rxe5 Ne7 18.b5 Nd5 19.Bd2 cxb5 20.Bxb5 Bd7 >21.Bxd7 Qxd7 22.c4 Nb6 >= (0.25): 15...Nd6 16.a3 axb4 17.axb4 Rxa1 18.Qxa1 b5 19.Qb1 h6 20.Ne5 >² (0.48): 15...g5 16.Nxg5 Bxg5 17.Bxg5 Qxg5 18.Bxf5 axb4 19.cxb4 Rd8 20.Bc2 Qf4 >21.Re4 Qd6 22.a3 >² (0.68): 15...Nh6 16.Bxh6 gxh6 17.Qd2 Bf8 18.a3 Qf6 19.Ne5 Bd6 >± (0.86): 15...e5 16.Nxe5 Nd6 17.Qc2 g6 18.a3 axb4 19.axb4 Rxa1 20.Rxa1 Bh4 >± (0.93): 15...axb4 16.gxf5 bxc3 17.fxe6 Bxe6 18.Qc2 h6 19.Qxc3 Bxa2 20.Qc2 Bd5 >21.Bh7+ Kh8 22.Rxa8 Qxa8 >± (1.25): 15...Nxd4 16.cxd4 axb4 17.Qc2 g6 18.Be5 Ra5 19.Rab1 Qd5 >+- (1.90): 15...h6 16.gxf5 axb4 17.fxe6 Bxe6 18.c4 Bg4 19.Be4 Bf6 20.Be5 > >Junior 5 does not like the Knight sacrifice. A better move is 15. ... Nh4. What >are the gains for Black if the Knight is sacrificed? The positional gains are >opening up the a-file, a passed pawn, and a weakening of White's kingside pawn >structure. Alright then, does these positional gains justify the sacrifice of a >piece? It does not, an old russian saying, a weakness is not a weakness unless >it can exploited. So the question is can Black exploit these "positional gains"? >I am afraid not, Black pieces are not mobilized to take advantage of the >situation. The passed pawn is undefended and can be captured. White has 3 pieces >developed in the kingside and can take advantage of the half-open g-file to >start a kingside attack. The half-open a-file is of no importance because >White's attack in the kingside is much faster than Black's attack on the >queenside. So PostModernist was lucky to get a draw in this game, GNUChess must >missed a win somewhere. > >GNUChess - PostModernist >r1bqr1k1/1p2bppp/2p1p3/5P2/3P1B2/2pB1N2/P4P1P/R2QR1K1 w - - 0 1 > >Analysis by Junior 5.0: > >± (1.08): 17.fxe6 Bxe6 18.Qc2 h6 19.Bh7+ Kf8 20.a3 Rxa3 21.Rxa3 Bxa3 22.Qxc3 Be7 >23.Rb1 Bc8 >± (0.75): 17.a4 Qa5 18.Re5 Qd8 19.Qc2 Bd6 20.fxe6 Bxe6 21.Bg5 f6 22.Rxe6 Rxe6 >23.Bc4 Qd7 >± (0.74): 17.Bc4 Bf6 18.fxe6 Bxe6 19.Bxe6 Rxe6 20.Rxe6 fxe6 21.Qb3 Bxd4 22.Qxb7 >c5 >² (0.65): 17.Re3 exf5 >² (0.62): 17.Qc2 exf5 18.Qxc3 Be6 19.a4 Qd5 >² (0.62): 17.Qc1 exf5 18.Qxc3 Be6 >² (0.59): 17.a3 >² (0.49): 17.Ne5 Rf8 18.fxe6 Bxe6 19.Bc2 Ba3 20.Qd3 Qh4 21.Qg3 >² (0.40): 17.Qb3 Ra3 18.Qc2 exf5 19.Bc1 Ra8 20.Qxc3 Be6 21.Ne5 Qd5 > >GNUChess decides to go for a Kingside attack with 17. Qc2. Junior 5 prefers 17. >fxe6 which opens up the position. Both plans are good. > >GNUChess - PostModernist >r3r2k/1p2bpp1/2p5/4BQ2/2qP4/2p2N2/P4P1P/R3R1K1 w - - 0 1 > >Analysis by Junior 5.0: > >+- (3.55): 24.Bxg7+ Kxg7 25.Qg4+ Bg5 26.Qxg5+ Kh7 27.Qh4+ Kg7 28.Ne5 Qd5 29.Qg3+ >Kf6 30.Qf4+ Kg7 31.Qg4+ Kh7 32.Qh3+ Kg8 33.Qxc3 >+- (3.50): 24.Qh5+ Kg8 25.Bxg7 Kxg7 26.Qg4+ Bg5 >+- (3.50): 24.Qh3+ Kg8 25.Bxg7 Kxg7 26.Qg4+ Bg5 >+- (1.90): 24.Rab1 b5 25.Qg4 f6 26.Bd6 Qf7 27.Rxe7 Rxe7 28.Bxe7 Qxe7 29.Qh5+ Kg8 >30.Re1 c2 >+- (1.78): 24.Bd6 Bf6 25.Rxe8+ Rxe8 26.Be5 Re6 27.Bxf6 Rxf6 28.Qh3+ Kg8 29.Qc8+ >Kh7 30.Ng5+ Kh6 >+- (1.78): 24.Bg3 Bf6 25.Rxe8+ Rxe8 26.Be5 Re6 >+- (1.77): 24.a3 Kg8 25.Ng5 f6 26.Qh7+ Kf8 27.Qg6 Kg8 28.Bd6 c2 >+- (1.77): 24.Qg4 f6 25.Bd6 Qf7 26.Bxe7 Rxe7 27.Rxe7 Qxe7 >+- (1.76): 24.Ng5 Bxg5 > >Here GNUChess misses his opportunity to capitalize his material advantage. It >chooses a very dubious plan of regrouping the pieces to stop the passed pawn. >Why???? Good question, instead of 24. Rac1??, played by GNUChess, there were 3 >good moves which White could have played to capitilize his material advantage as >shown by Junior 5, 24. Bxg7+, 24. Qh5+, 24. Qh3+. Although the plan chosen >byGNUChess is dubious, White still retains its positional advantage until the >final mistake, move 27. Qd7?? which throws away winning chances. The Queen finds >herself cut off from the remaing pieces and GNUChess goes for pawn hunting, >totally mis-evaluating the position. After that Black's passed pawn gains >momentum. > >Conclusion: the Knight sacrifice is a blunder. > >Laurence Laurence, Thank you very much for the time you spent looking at this. This is exactly the sort of analysis I can't do very well myself. Even if I get crafty or gnuchess to look at my program's games, most of the time I can't really understand why they think a particular move is bad. Your analysis has given me a lot of food for thought. Best regards, Andrew
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