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Subject: Re: Sometimes they go 'boom'

Author: John Merlino

Date: 13:23:53 09/20/02

Go up one level in this thread


On September 20, 2002 at 14:18:38, John Merlino wrote:

>On September 20, 2002 at 13:30:09, Gian-Carlo Pascutto wrote:
>
>>[D]4b3/6p1/5p1p/5P1P/3kPK2/1p6/1P2B3/8 b - - 0 1
>>
>>My engine just managed to lose what looked like a dead-drawn
>>endgame against a Crafty clone on ICC. I couldn't understand
>>what happened. I still don't know exactly, but it looks like
>>some kind of hashing/draw-by-rep/nullmove artifact ;)
>>
>>But my program doesn't seem to be the only one that
>>gets funny on this position:
>
>Here's what Chessmaster 9000 says on this position. Not sure if it is also
>"funny":
>
>Time	Depth	Score	Positions	Moves
>0:00	3/7	-0.38	4743		1...Bc6 2.Bd1 Ba4 3.Be2 Be8 4.Bf3
>					Bb5
>0:00	4/8	-0.36	10780		1...Bc6 2.Bd1 Ba4 3.Kf3 Ke5 4.Ke3
>					Be8 5.Bxb3 Bxh5
>0:00	4/8	-0.43	19865		1...Bf7 2.Bd1 Bc4 3.Bg4 Bd3 4.Bd1
>					Bc2 5.Bf3
>0:00	5/9	-0.44	26752		1...Bf7 2.Bd1 Kd3 3.e5 fxe5+ 4.Kxe5
>					Kd2 5.f6 Kxd1 6.fxg7 Bg8
>0:00	6/10	-0.69	67861		1...Bf7 2.Bf3 Kd3 3.e5 fxe5+ 4.Kxe5
>					Kc2 5.f6 gxf6+ 6.Kxf6 Kxb2 7.Kxf7
>					Kc2
>0:01	6/10	-1.48	98615		1...Ba4 2.Bf1 Bc6 3.Be2 Bxe4 4.Bb5
>					Bd3 5.Be8 Bc4 6.Bc6 Be2
>0:01	7/11	-0.97	152287		1...Ba4 2.Bf3 Kd3 3.e5 Kc2 4.e6
>					Kxb2 5.Be4 Be8 6.Ke3 Bxh5 7.Kd4
>0:02	8/12	-1.21	242560		1...Ba4 2.Bf3 Kd3 3.e5 Kc2 4.e6
>					Kxb2 5.Be4 Be8 6.Ke3 Kc3 7.Bf3
>0:05	9/13	-1.41	531277		1...Ba4 2.Bf3 Kd3 3.e5 Kc2 4.e6
>					Kxb2 5.Be4 Ka1 6.Ke3 b2 7.Kd4 Be8
>					8.Kc5 Bxh5
>0:09	10/14	-1.21	969537		1...Ba4 2.Bf3 Kd3 3.e5 Kc2 4.e6
>					Kxb2 5.Ke4 Kc1 6.Kd5 b2 7.Be4 Bb3+
>					8.Kd6 Bc2 9.Bxc2 Kxc2
>0:22	11/15	-1.41	2239357		1...Ba4 2.Kf3 Bc6 3.Kf4 Bxe4 4.Bb5
>					Bd3 5.Be8 Bc4 6.Bd7 Kd5 7.Be6+
>					Kc5 8.Bc8 Kd6 9.Bb7 Bd3
>0:40	12/16	-1.52	4027500		1...Ba4 2.Kf3 Bc6 3.Kf4 Bxe4 4.Bb5
>					Bc2 5.Be2 Bd3 6.Bf3 Bc4 7.Bg4 Bd5
>					8.Bd1 Kd3 9.Bg4
>1:52	13/17	-1.54	11346643	1...Ba4 2.Bd1 Kd3 3.e5 Kd2 4.Bf3
>					Kc2 5.e6 Kxb2 6.Kg4 Kc1 7.Be4 b2
>					8.Kh4 Bc6 9.Bd3 b1=Q 10.Bxb1 Kxb1
>3:58	14/18	-1.56	23785267	1...Ba4 2.Bd1 Kd3 3.e5 Kd2 4.Bf3
>					Kc2 5.e6 Kxb2 6.Kg3 Kc1 7.Be4 b2
>					8.Kh4 Bc6 9.Bd3 b1=Q 10.Bxb1 Kxb1
>					11.Kg4
>
>jm

Here's what my wonderful new P4-2.66 says:

Time	Depth	Score	Positions	Moves
0:00	6/10	-0.69	67114		1...Bf7 2.Bf3 Kd3 3.e5 fxe5+ 4.Kxe5
					Kc2 5.f6 gxf6+ 6.Kxf6 Kxb2 7.Kxf7
					Kc2
0:00	6/10	-1.48	101882		1...Ba4 2.Bf1 Bc6 3.Be2 Bxe4 4.Bb5
					Bd3 5.Ba4 Bc4 6.Bc6 Be2
0:00	7/11	-1.24	154064		1...Ba4 2.Bf3 Kd3 3.e5 Kc2 4.Be4+
					Kxb2 5.e6 Kc1 6.Ke3 b2 7.Kd4 b1=Q
					8.Bxb1 Kxb1
0:00	8/12	-1.11	243418		1...Ba4 2.Bf3 Kd3 3.e5 Kc2 4.e6
					Kxb2 5.Ke4 Kc1 6.Kd5 b2 7.Be4 b1=Q
					8.Bxb1 Kxb1
0:01	9/13	-1.37	551010		1...Ba4 2.Bd1 Kd3 3.e5 Kd2 4.Bg4
					Kc2 5.e6 Kxb2 6.Ke4 Kc2 7.Be2 Bc6+
					8.Kd4 b2
0:02	10/14	-1.21	1056757		1...Ba4 2.Bf3 Kd3 3.e5 Kc2 4.e6
					Kxb2 5.Ke4 Kc1 6.Kd5 b2 7.Be4 Bb3+
					8.Kd6 Bc2 9.Bxc2 Kxc2
0:05	11/15	-1.39	2150529		1...Ba4 2.Kf3 Bc6 3.Kf4 Bxe4 4.Bb5
					Bd5 5.Bd7 Bc4 6.Be8 Kc5 7.Ke3 Bg8
					8.Bg6 Bd5
0:10	12/16	-1.51	3730489		1...Ba4 2.Kf3 Bc6 3.Kf4 Bxe4 4.Bb5
					Bd5 5.Bd7 Bc4 6.Bc6 Bf7 7.Bf3 Bd5
					8.Be2 Bc4 9.Bf3 Bd3
0:24	13/17	-1.56	9124305		1...Ba4 2.Bd1 Kd3 3.e5 Kd2 4.Bf3
					Kc2 5.Be4+ Kxb2 6.e6 Kc1 7.Kg4
					b2 8.Kh4 Bc6 9.Bd3 b1=Q 10.Bxb1
					Kxb1 11.Kg4
0:42	14/18	-1.56	16053836	1...Ba4 2.Bd1 Kd3 3.e5 Kd2 4.Bf3
					Kc2 5.e6 Kxb2 6.Kg3 Kc1 7.Be4 b2
					8.Kh4 Bc6 9.Bd3 b1=Q 10.Bxb1 Kxb1
					11.Kg4
1:20	15/19	-1.61	29921228	1...Ba4 2.Bd1 Kd3 3.e5 Kd2 4.Bf3
					Kc2 5.e6 Kxb2 6.Kg3 Be8 7.Kg4 Kc3
					8.Be4 Kd4 9.Bb1 Ke5 10.Kh4 Kd6
					11.Be4
2:39	16/20	-1.64	57836732	1...Ba4 2.Bd1 Kd3 3.e5 Kd2 4.Bf3
					Kc2 5.e6 Kxb2 6.Kg3 Kc1 7.Be4 b2
					8.Kh4 b1=Q 9.Bxb1 Kxb1 10.Kg4 Kc1
					11.Kh4 Kd2 12.Kg4
6:39	17/21	-2.08	139326723	1...Ba4 2.Bd1 Kd3 3.e5 Kd2 4.Bf3
					Kc2 5.e6 Kxb2 6.Kg3 Ka1 7.Be4 b2
					8.Kg4 Bd1+ 9.Kh4 b1=Q 10.Bxb1 Kxb1
					11.e7 Ba4 12.Kh3 Be8 13.Kg4 Kc2
14:31	18/22	-2.23	297884319	1...Ba4 2.Bd1 Kd3 3.e5 Kd2 4.Bf3
					Kc2 5.e6 Kxb2 6.Kg3 Kc1 7.Be4 b2
					8.Kh4 Bc2 9.Bxc2 Kxc2 10.e7 b1=Q
					11.e8=Q Qh1+ 12.Kg3 Qg1+ 13.Kh3
					Qf1+ 14.Kg3 Qxf5 15.Qe2+ Kc3 16.Qe3+
					Kc4

So, does Black really have a win here?

jm



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