Author: John Merlino
Date: 07:56:51 12/13/02
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On December 13, 2002 at 10:08:02, Uri Blass wrote: >On December 13, 2002 at 09:58:37, Art Basham wrote: > >>Even my old WChess program could not find 1. h6! >> >>White promotes the h pawn... but only to be sacrificed! >> >>[D]8/1p2pk2/p4p1P/4p2K/4P1P1/P4P2/1P5R/6r1 w - - 0 1 > >Movei needs only 9725 nodes and 5 plies to fail high on h7. >I am surprised if Wchess cannot find it. > >50914 <first : 5 134 10 9725 h6h7 >50924 <first : 5 163 11 10161 h6h7 >50934 <first : 5 651 12 11660 h6h7 g1g2 h7h8n f7g7 h2g2 g7h8 h5g6 h8g8 > >Uri CM9000, on a humble P3-733, after 1:37 says h7 is a Mate in 12, then announces Mate in 10 after a little less than five minutes: Time Depth Score Positions Moves 0:00 1/4 1.52 4950 1.Rh3 Rb1 2.g5 fxg5 3.Kxg5 Rxb2 0:00 1/5 1.48 8174 1.Rh3 Rg2 2.b3 Rf2 3.h7 Kg7 0:00 1/6 1.50 16558 1.Rh3 Rg2 2.b3 b5 3.a4 bxa4 4.bxa4 0:00 2/7 1.53 39950 1.Rh3 Rg2 2.b3 Rf2 3.g5 Rg2 4.gxf6 exf6 0:02 2/7 8.21 66288 1.h7 Rg2 2.Rxg2 Kg7 3.g5 Kxh7 4.g6+ Kg7 0:02 3/8 9.09 69123 1.h7 Rg2 2.Rxg2 Kg7 3.Rd2 Kxh7 4.Rd7 Kg8 5.Rxb7 0:02 4/9 9.08 77483 1.h7 Rg2 2.Rxg2 Kg7 3.Rd2 Kxh7 4.Rd7 Kg8 5.Rxe7 0:02 5/10 9.31 113585 1.h7 Rg2 2.Rxg2 Kg7 3.Rd2 Kxh7 4.Rd7 b6 5.Rxe7+ Kg8 6.Kg6 0:20 6/11 14.59 1826560 1.h7 Rd1 2.h8=Q Rd6 3.Qh7+ Ke8 4.Rc2 Kd7 5.Qf5+ Ke8 6.Rc8+ Rd8 7.Qe6 Rxc8 8.Qxc8+ Kf7 9.Qxb7 a5 10.Qd5+ e6 11.Qxa5 0:34 7/12 18.18 3374674 1.h7 Rd1 2.h8=Q Rc1 3.Qh7+ Ke6 4.Qg8+ Kd7 5.Rd2+ Kc6 6.Qc8+ Kb6 7.Qxc1 a5 8.Rd5 Ka6 9.Qc4+ Ka7 10.Rxa5+ Kb8 1:37 8/13 Mate12 10558553 1.h7 Rd1 2.h8=Q Rc1 3.Qh7+ Ke6 4.Qg8+ Kd7 5.Rd2+ Kc6 6.Qe6+ Kb5 7.Rd7 Ka4 8.Rxb7 Rh1+ 9.Kg6 Rh6+ 10.Kxh6 Ka5 11.Qb6+ Ka4 12.Qxa6# 4:52 9/14 Mate10 34253533 1.h7 Rd1 2.h8=Q Rd3 3.g5 fxg5 4.Kxg5 Rxf3 5.Rh7+ Ke6 6.Qd8 Rg3+ 7.Kh4 Rg4+ 8.Kxg4 Kf6 9.Qxe7+ Kg6 10.Qg7# It appears that the sacrifice you are referring to is not best play for Black, as in the final PV above, the promoted pawn is never captured. Apparently, attempting to capture the h-pawn leads to a faster mate. jm
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