Author: John Merlino
Date: 13:10:47 01/19/03
Go up one level in this thread
On January 19, 2003 at 06:03:14, David Rasmussen wrote: >On January 18, 2003 at 22:16:15, John Merlino wrote: > >> >>Some brief analysis with Chessmaster 9000 seems to say that 54.Bg1 may have been >>the move that started the downfall. CM9000 prefers g4 with an eval of exactly >>zero. >> >>After that things go downhill pretty quickly. Even though CM agrees with all of >>the moves after that, by move 61, the eval is already about -1.5. Any "errors" >>after that are probably not as important.... >> >>jm > >Thank you very much, John, for taking the time to do this! I will look into it >later. > >[D]3b4/8/3k4/p2Pp1p1/2P5/pKP1B1P1/Nn6/8 w - - 0 54 > >What could be the missing knowledge that makes Chezzz play Bg1 and avoid g4? And >is g4 _necesary_ or is Bg1 specifically an _error_? > >One think I can think of that Chezzz lacks, is that it would be a good idea to >fixate the g5 pawn on a dark square, because black's bishop is restrained and >because it can be attacked by white's bishop. That is a good reason to choose >g4. But are there "tactical" reasons why Bg1 is wrong? Another thing that is >missing from Chezzz is knowledge about certain passed pawn situations. >Specifically, it knows nothing about outside passed pawns. I think this missing >knowledge could play a role, if not now, then later in the game. But you say >there are no important errors later in the game, so I will focus on this >position. I'm definitely the wrong person to be asking this, since I am a complete patzer. Although, your theory of keeping the pawn on g5 looks right to me. Here is what CM9000 says before 54.Bg1. This is on a humble P3-733, so you could divide the times by four to reflect today's typical top-end hardware: Time Depth Score Positions Moves 0:00 1/6 0.27 10329 54.g4 a4+ 55.Kb4 e4 56.Bg1 Bc7 57.Bh2+ Kd7 0:00 1/7 0.28 33035 54.g4 e4 55.Bd4 a4+ 56.Kb4 Bc7 57.Nc1 Nd3+ 58.Nxd3 exd3 59.Kxa3 0:00 2/8 0.10 71101 54.g4 e4 55.Bd4 Be7 56.Nc1 a4+ 57.Kb4 Nd3+ 58.Nxd3 exd3 59.Kxa3 d2 0:01 3/9 0.13 134403 54.g4 e4 55.Bg1 Nd3 56.Kxa3 Ne5 57.Bh2 e3 58.Bxe5+ Kxe5 59.Kb3 0:03 4/10 0.13 287924 54.g4 e4 55.Ba7 Bf6 56.Bb6 a4+ 57.Kb4 Be5 58.Bd4 Bf4 59.Bc5+ Kc7 60.Be7 0:08 5/11 0.09 750776 54.g4 e4 55.Ba7 Bc7 56.Bg1 Nd3 57.Bd4 Ne5 58.Bxe5+ Kxe5 59.Kxa3 e3 60.Kb3 0:22 6/12 0.03 1945616 54.g4 e4 55.Bg1 Be7 56.Bb6 a4+ 57.Kb4 Ke5+ 58.Kb5 Nd3 59.Kxa4 Kf4 60.Nb4 Kxg4 61.Kxa3 1:01 7/13 0.00 5267806 54.g4 e4 55.Bg1 Nd1 56.Bd4 Nb2 57.Bg1 2:27 8/14 0.00 12321866 54.g4 e4 55.Bg1 Nd1 56.Bd4 Nb2 57.Bg1 5:39 9/15 0.00 29899612 54.g4 e4 55.Bg1 Nd1 56.Bd4 Nb2 57.Bg1 16:56 10/16 0.00 79246492 54.g4 e4 55.Bg1 Nd1 56.Bd4 Nb2 57.Bg1 43:12 11/17 0.00 211218022 54.g4 e4 55.Bg1 Nd1 56.Bd4 Nb2 57.Bg1 Draw all the way.... But here is what CM9000 says after 54.Bg1: Time Depth Score Positions Moves 0:00 1/6 0.07 11399 54...g4 55.Ba7 a4+ 56.Kb4 e4 57.Be3 Ba5+ 58.Kb5 0:00 1/7 0.00 32524 54...g4 55.Ba7 e4 56.Be3 Bf6 57.Bf4+ Kc5 58.Be3+ Kd6 0:00 2/8 0.00 42113 54...g4 55.Ba7 e4 56.Be3 Bf6 57.Bf4+ Kc5 58.Be3+ Kd6 0:01 3/9 0.00 83123 54...g4 55.Ba7 e4 56.Be3 Bf6 57.Bf4+ Kc5 58.Be3+ Kd6 0:03 4/10 0.00 228162 54...g4 55.Ba7 e4 56.Bb8+ Kc5 57.Ba7+ Kd6 0:07 5/11 0.00 581605 54...g4 55.Ba7 e4 56.Be3 Bf6 57.Ba7 Bg7 58.Bb8+ Kc5 59.Ba7+ Kd6 0:25 6/12 -0.14 2249065 54...g4 55.Be3 a4+ 56.Kb4 e4 57.Bc5+ Kd7 58.Kxa3 Nd3 59.Be3 Bc7 60.c5 Bxg3 61.Kxa4 Bf4 62.Bxf4 Nxf4 1:03 7/13 -0.20 5742894 54...g4 55.Ba7 e4 56.Be3 Bf6 57.Ba7 Nd3 58.Kxa3 Be5 59.Nc1 Bxc3 60.Nxd3 exd3 61.Bb8+ Kd7 62.Kb3 2:51 8/14 -0.34 15968244 54...g4 55.Ba7 e4 56.Be3 Bf6 57.Ba7 Nd3 58.Kxa3 Bg5 59.Bb8+ Kc5 60.Kb3 a4+ 61.Kxa4 Kxc4 62.d6 e3 6:21 9/15 -0.45 36062199 54...g4 55.Ba7 e4 56.Be3 Bf6 57.Ba7 Nd3 58.Kxa3 Bg5 59.Bb8+ Ke7 60.c5 Nxc5 61.c4 Bd2 62.Bc7 Nb7 18:28 10/16 -0.58 105493342 54...g4 55.Ba7 e4 56.Be3 Bf6 57.Ba7 Kc7 58.c5 e3 59.Bb6+ Kb7 60.Kc2 Na4 61.Kd3 Nxb6 62.cxb6 Bg5 63.c4 Kxb6 47:21 11/17 -0.65 268746684 54...g4 55.Ba7 e4 56.Be3 Bf6 57.Bb6 a4+ 58.Kb4 Be5 59.Bc5+ Kd7 60.Bg1 Bd6+ 61.c5 Nd3+ 62.Kxa3 Nxc5 63.c4 Nd3+ 64.Kxa4 Bxg3 65.c5 Bc7 You can see that the eval is consistently dropping. jm
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