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Subject: Re: Another interesting Anti-Null move position (from a real game)

Author: John Merlino

Date: 16:04:22 06/14/04

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On June 14, 2004 at 16:31:17, Jaime Benito de Valle Ruiz wrote:

>[d]8/8/1p4p1/p5kp/Pp1QP1Pq/1P6/6K1/8 w - - 0 62
>
>White moves and wins!
>Can your engine find the right answer and give the proper "crushing" score
>(around 9 pawns!) along with a proper PV? How long does it take?
>Mine doesn't find anything after a long long time (over an hour), but with
>null-move disabled, it takes only a few seconds to show the full PV.
>(Some engines find the right answer, but with a small score, an absurd PV, and
>they change their mind some plies later)
>
>In this position the black king is in a very delicate position: After a couple
>of moves, if the black queen moves, white checkmates inmediately, so both kings
>and queens must remain still while pawns play on their own.
>
>Any good suggestion to avoid this problem with null-move?
>
>Regards,
>
>  Jaime

Well, you'll have to ask Johan. The King uses null-move and CM_SKR gives a
"crushing score" (7.76) in less than one second on an AMD 2500+:

Time	Depth	Score	Positions	Moves
0:00	1/3	-0.28	1764		62.gxh5 Qg4+ 63.Kh2 Qf4+ 64.Kg2
					gxh5 65.Qg7+ Kh4
0:00	1/3	0.39	3672		62.Qe3+ Kxg4 63.e5 Qe7 64.e6
0:00	1/4	-0.05	6377		62.Qe3+ Kxg4 63.e5 Qe7 64.e6 h4
0:00	1/5	0.04	18238		62.Qe3+ Kxg4 63.e5 Qe7 64.e6 h4
					65.Kh2
0:00	1/5	1.18	36479		62.Qd2+ Kxg4 63.Qe3 b5 64.Qf3+
					Kg5 65.axb5 a4
0:00	1/6	1.18	42403		62.Qd2+ Kxg4 63.Qe3 b5 64.axb5
					a4 65.Qf3+ Kg5
0:00	1/7	1.11	62825		62.Qd2+ Kxg4 63.Qe3 b5 64.axb5
					a4 65.b6 axb3 66.Qxb3
0:00	1/8	6.24	99795		62.Qd2+ Kxg4 63.Qe3 b5 64.axb5
					a4 65.b6 axb3 66.b7 b2 67.Qf3+
					Kg5 68.b8=Q
0:00	1/9	7.76	142454		62.Qd2+ Kxg4 63.Qe3 b5 64.axb5
					a4 65.b6 axb3 66.b7 b2 67.Qf3+
					Kg5 68.b8=Q Qg4+ 69.Qxg4+ hxg4
					70.Qe5+ Kh4 71.Qxb2
0:00	1/10	7.76	218861		62.Qd2+ Kxg4 63.Qe3 b5 64.axb5
					a4 65.b6 axb3 66.b7 b2 67.Qf3+
					Kg5 68.b8=Q Qg4+ 69.Qxg4+ hxg4
					70.Qe5+ Kh4 71.Qxb2
0:01	2/11	7.76	370451		62.Qd2+ Kxg4 63.Qe3 b5 64.axb5
					a4 65.b6 axb3 66.b7 b2 67.Qf3+
					Kg5 68.b8=Q Qg4+ 69.Qxg4+ hxg4
					70.Qe5+ Kh4 71.Qxb2
0:03	3/12	8.45	940906		62.Qd2+ Kxg4 63.Qe3 b5 64.axb5
					a4 65.b6 axb3 66.b7 b2 67.Qe2+
					Kg5 68.b8=Q Qh1+ 69.Kxh1 b1=Q+
					70.Kh2 Qb3 71.Qd2+ Kf6
0:23	4/13	12.06	8261572		62.Qd2+ Kxg4 63.Qe3 Qh3+ 64.Qxh3+
					Kf4 65.Qh4+ Ke5 66.Qe7+ Kd4 67.e5
					Kc3 68.Qf7 b5 69.e6 bxa4 70.e7
					g5 71.Qc4+ Kb2 72.Qe2+ Kxb3 73.e8=Q
0:49	5/14	12.96	18224345	62.Qd2+ Kxg4 63.Qe3 Qh3+ 64.Qxh3+
					Kf4 65.Qh4+ Ke5 66.Qe7+ Kd4 67.e5
					Kc3 68.Qf7 b5 69.e6 bxa4 70.e7
					h4 71.e8=Q h3+ 72.Kxh3 axb3 73.Qxg6
1:56	6/15	14.01	44019358	62.Qd2+ Kf6 63.Qd8+ Ke5 64.Qxh4
					hxg4 65.Qxg4 Kd4 66.Qxg6 Kc3 67.e5
					Kxb3 68.Qb1+ Kxa4 69.e6 b3 70.e7
					Kb4 71.Qe1+ Kc4 72.Qc1+ Kb4 73.e8=Q

jm



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