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Subject: Re: Chezzz - Hossa CCT5

Author: John Merlino

Date: 13:10:47 01/19/03

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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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