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Subject: Re: White to Play and Win

Author: John Merlino

Date: 10:38:09 04/25/05

Go up one level in this thread


On April 25, 2005 at 05:50:11, Joachim Rang wrote:

>On April 24, 2005 at 21:46:00, John Merlino wrote:
>
>>On April 24, 2005 at 21:07:45, pavel wrote:
>>
>>>[D]1b6/4P3/1P2PN2/8/8/P1k5/P1p2P2/K5B1 w
>>>
>>>http://www.edcollins.com/chess/under-promote.htm
>>>
>>>Any program find the checkmate?
>>>
>>>pavs
>>
>>Checkmate is a VERY long way away from the initial position -- maybe as many as
>>30 moves. That's a bit too far for an engine to see.
>>
>>However, there MIGHT be an error in this puzzle. The answer that is given is:
>>
>>[Event ""]
>>[Site ""]
>>[Date "2005.4.24"]
>>[Round ""]
>>[White "Merlin"]
>>[Black "Merlin"]
>>[TimeControl "-"]
>>[Result "*"]
>>[Setup "1"]
>>[FEN "1b6/4P3/1P2PN2/8/8/P1k5/P1p2P2/K5B1 w - - 0 1"]
>>
>>1.Ne4+ Kd3 2.Nc5+ Kc3 3.Nb3 Be5 4.f4 Bf6 5.e8=N Bh8 6.f5 Be5 7.Bh2 Bxh2
>>8.b7 Be5 9.b8=B Bxb8 10.Nc7 Bxc7 11.e7 Be5 12.e8=R Bf6 13.Re6 Bg7 14.f6
>>
>>and White wins.
>>
>>But it seems that 8...Kd3 9.Nc1+ Kd2 10.Kb2 Be5+ 11.Kb3 Kxc1 12.Nc7 Bxc7 13.e7
>>Kd2 14.e8=Q c1=Q might hold for Black. Here's the position after my line:
>>
>>[D]4Q3/1Pb5/8/5P2/8/PK6/P2k4/2q5 w - - 0 15
>>
>>It would take a lot of analysis, much more than I'm willing to commit to it. :-)
>>
>>jm
>
>Although your line is definitely an improvment for black I don't think that it
>holds the position. After 2 minutes Shredder gives here already +5 and the eval
>is climbing.
>
>
>4Q3/1Pb5/8/5P2/8/PK6/P2k4/2q5 w - -
>
>Engine: Shredder 9 UCI (128 MB)
>von Stefan Meyer-Kahlen
>
>10/28  0:01   +3.94    15.Dd7+ (407.698) 357
>
>11/32  0:02   +3.94    15.Dd7+ (841.719) 332
>
>12/33  0:04   +3.94    15.Dd7+ (1.550.156) 335
>
>13/37  0:10   +3.94    15.Dd7+ Ke3 16.Dd5 Kf4 17.f6 Db1+
>                       18.Ka4 Db6 19.f7 Da6+ 20.Kb3 Db6+
>                       21.Kc2 (3.608.473) 334
>
>14/40  0:27   +4.19++  15.Dd7+ Ke3 (8.645.204) 318
>
>14/40  0:45   +4.68    15.Dd7+ Ke3 16.Dd5 Lf4 17.f6 Dc7
>                       18.f7 Db6+ 19.Kc4 Da6+ 20.Kc5 Da5+
>                       21.Kc6 Dc7+ 22.Kb5 Ld6 23.De6+ Kd2 (14.816.689) 325
>
>15/40  1:29   +4.93++  15.Dd7+ Ke3 (27.845.916) 311
>
>15/42  2:00   +5.43++  15.Dd7+ Ke3 (38.646.693) 321
>
>15/42  2:52   +5.58    15.Dd7+ Ke3 16.Dd5 Kf4 17.f6 De3+
>                       18.Kc2 Db6 19.a4 (56.024.918) 325
>
>16/44  4:59   +5.36    15.Dd7+ Ke3 16.Dd5 Lf4 17.f6 Dc7
>                       18.f7 Ld6 19.a4 Lc5 20.a5 Kf4
>                       21.Dc4+ Ke3 22.De6+ Kd4 23.Dg4+ Ke3 (102.021.801) 340
>
>regards Joachim

Here's what CMX-Yoda v25 on a P4-2.4 has to say. Definitely not as convincing,
as the increase in eval is much less pronounced than with Shredder. I have no
idea which engine is more correct:

Time	Depth	Score	Positions	Moves
0:00	1/4	1.68	7289		1.Qd7+ Ke3 2.Qd5 Qb1+ 3.Ka4 Qb6
0:00	1/5	1.87	24967		1.Qd7+ Ke3 2.Qd5 Kf4 3.f6 Be5
0:00	1/6	2.15	83938		1.Qd7+ Ke3 2.Qd5 Bb8 3.f6 Qb1+
					4.Ka4 Qb6
0:00	2/7	1.88	138373		1.Qd7+ Ke3 2.Qd5 Kf4 3.f6 Qe3+
					4.Kc2 Be5 5.f7 Qc3+ 6.Kd1
0:01	2/8	2.10	307568		1.Qd7+ Ke3 2.Qd5 Kf4 3.f6 Qb1+
					4.Ka4 Qb6 5.f7 Bd6 6.Qd3
0:05	2/9	2.21	993630		1.Qd7+ Ke3 2.Qd5 Kf4 3.f6 Qe3+
					4.Kc4 Qxa3 5.Qd2+ Kf3 6.Qd3+ Qxd3+
					7.Kxd3 Bd6
0:18	3/10	2.34	3286945		1.Qd7+ Ke3 2.Qd5 Bb8 3.f6 Qb1+
					4.Ka4 Qf1 5.f7 Qa6+ 6.Kb3 Qb6+
					7.Kc2 Qg6+ 8.Kc1 Qf6
0:28	3/11	2.33	5128850		1.Qd7+ Ke3 2.Qd5 Bb8 3.f6 Qb1+
					4.Ka4 Qf1 5.f7 Qa6+ 6.Kb3 Qb6+
					7.Kc2 Qg6+ 8.Kc1 Qf6 9.Qc5+ Kd3
1:00	3/12	2.34	11377557	1.Qd7+ Ke3 2.Qd5 Bf4 3.Kb4 Qe1+
					4.Kb5 Kf2 5.Qd4+ Kf3 6.Qxf4+ Kxf4
					7.b8=Q+ Kxf5 8.Qc8+ Kg6 9.Qc6+
					Kf5 10.a4
1:56	4/13	2.41	22724932	1.Qd7+ Ke3 2.Qd5 Bf4 3.a4 Qb1+
					4.Ka3 Kf2 5.a5 Bb8 6.a6 Qb6 7.Qd2+
					Kf3 8.Qd3+ Kf4 9.Ka4 Kg5
4:22	5/14	2.59	53247445	1.Qd7+ Ke3 2.Qd5 Bf4 3.f6 Qb1+
					4.Ka4 Qg6 5.f7 Qa6+ 6.Kb3 Qb6+
					7.Kc4 Qa6+ 8.Kc5 Qf6 9.Kb5 Bd6
					10.Qb3+ Kf2 11.Ka6
10:50	6/15	2.78	134839777	1.Qd7+ Ke3 2.Qd5 Bf4 3.f6 Qb1+
					4.Ka4 Qg6 5.f7 Qa6+ 6.Kb3 Qb6+
					7.Kc4 Qa6+ 8.Kc5 Qa5+ 9.Kc6 Qc7+
					10.Kb5 Bd6 11.Qc6 Qxf7 12.Qxd6
					Qxb7+ 13.Qb6+ Qxb6+ 14.Kxb6

jm



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