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Subject: Re: test position - delaying the inevitable

Author: Jon Dart

Date: 08:56:22 01/09/03

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On January 08, 2003 at 17:56:21, John Merlino wrote:

>On January 08, 2003 at 16:30:38, Jon Dart wrote:
>
>>This position came up in an offline test game, Arasan 6.2 vs. Lambchop 10.88:
>>
>>[D] 1k6/q7/2Q5/r3pp2/6p1/8/5rPP/5RK1 w - -
>>
>>White can delay the inevitable with a series of checks, beginning with Qe8+, but
>>eventually he will run out of checks and lose, I think. This is something that
>>is typically hard for computers to see. Arasan (White) thought it was fine at
>>this point.
>>
>>Crafty 18.10 fails low on this position at ply 13, but then it takes a long time
>>to resolve the fail-low: I gave it 20 minutes on a Xeon 1.7GHz, and it was still
>>searching.
>>
>>Pharaon gets a score of about -2.5 at ply 12, but it went up again on ply 13,
>>and then like Crafty it just hangs at ply 14 for a really long time.
>>
>>--Jon
>
>On a relatively slow P3-733, Chessmaster 9000 says:
>
>Time	Depth	Score	Positions	Moves
>0:00	1/3	-1.05	6233		1.Qe8+ Kc7 2.Qe7+ Kc6 3.Qe6+ Kb7
>					4.Qb3+ Ka8 5.Rxf2
>0:00	1/4	-0.86	11407		1.Qe8+ Kc7 2.Qe7+ Kc6 3.Qe6+ Kb7
>					4.Qb3+ Qb6 5.Qxb6+ Kxb6 6.Kxf2
>0:00	1/5	-0.91	24513		1.Qe8+ Kc7 2.Qe7+ Kc6 3.Qe6+ Kc5
>					4.Rc1+ Rc2 5.Rxc2+ Kb4+ 6.Kf1 Ra1+
>					7.Ke2
>0:00	1/6	-1.22	45695		1.Qe8+ Kc7 2.Qe7+ Kc6 3.Qe6+ Kc5
>					4.Rc1+ Rc2 5.Rxc2+ Kb4+ 6.Kf1 Ra1+
>					7.Ke2 Qg1
>0:01	1/7	-1.37	98187		1.Qe8+ Kc7 2.Qe7+ Kc6 3.Qe6+ Kb5
>					4.Qb3+ Kc5 5.Qe3+ Kc6 6.Qxf2 Qxf2+
>					7.Kxf2 Ra2+ 8.Kg1
>0:02	1/7	-1.17	141641		1.Qd6+ Kc8 2.Qc6+ Kd8 3.Qd6+ Qd7
>					4.Qb6+ Ke7 5.Qxf2 e4 6.Qh4+ Ke6
>					7.Qh6+ Ke5
>0:03	1/8	-1.35	296127		1.Qd6+ Kc8 2.Qc6+ Kd8 3.Qd6+ Ke8
>					4.Qe6+ Kf8 5.Qf6+ Qf7 6.Qxf7+ Kxf7
>					7.Kxf2 Ra2+ 8.Kg1 Ke6 9.Rc1
>0:07	2/9	-1.22	604348		1.Qd6+ Kc8 2.Qc6+ Kd8 3.Qd6+ Ke8
>					4.Qe6+ Kf8 5.Qf6+ Qf7 6.Qh8+ Ke7
>					7.Qh4+ Ke6 8.Qxf2 Rd5 9.Rc1
>0:18	3/10	-1.27	1567157		1.Qd6+ Kc8 2.Qc6+ Kd8 3.Qd6+ Ke8
>					4.Qe6+ Kf8 5.Qf6+ Qf7 6.Qd8+ Kg7
>					7.Qg5+ Kh7 8.Kxf2 Ra3 9.Kg1
>0:43	4/11	-1.18	3838943		1.Qd6+ Kc8 2.Qc6+ Kd8 3.Qd6+ Ke8
>					4.Qe6+ Kf8 5.Qf6+ Qf7 6.Qd8+ Kg7
>					7.Qg5+ Kh7 8.Kxf2 Ra2+ 9.Kg1 Qa7+
>					10.Kh1 Qd7
>1:51	5/12	-1.14	9889643		1.Qd6+ Kc8 2.Qc6+ Kd8 3.Qd6+ Ke8
>					4.Qe6+ Kf8 5.Qf6+ Qf7 6.Qd8+ Kg7
>					7.Qg5+ Kh7 8.Kxf2 Ra2+ 9.Kg1 Qa7+
>					10.Kh1 Qd7 11.Qh5+ Kg8 12.Qg5+ Kh8
>7:37	6/13	-1.15	41238547	1.Qd6+ Kc8 2.Qc6+ Kd8 3.Qd6+ Ke8
>					4.Qe6+ Kf8 5.Qf6+ Kg8 6.Qg6+ Qg7
>					7.Qe8+ Qf8 8.Qxf8+ Kxf8 9.Kxf2
>					Kg7 10.Re1 Ra2+ 11.Kg1 Kf6 12.Kf1
>
>It appears that, if Black wants to avoid the draw by perpetual, he needs to
>sacrifice the f2 rook, going into the endgame up one pawn, which may or may not
>be winnable.
>
>jm



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