Author: John Merlino
Date: 11:30:32 01/30/02
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On January 30, 2002 at 11:58:49, Andrew Smith wrote: >This is an interesting position. In particular, the fourth move in the winning >line. Qg7 Kh2 f8Q Qb6+ Kh6 *Bc6*. Other moves are possibly winning but 4. Bc6 >looks to be the best by far. I let gambit tiger analyse this over night, and it >couldn't come up with 4. Bc6. What do other programs think here on fast >hardware? Can they find Bc6 in the initial position? > >[D]5Q2/5P1b/8/7K/8/1q4k1/1p4B1/8 w - - 0 1 Your post is a little confusing, because your line above contains at least two errors (2...Qb6 is not check, because the White King is on h5, and obviously 3.Kh6 is not a legal move after 2...Qb6). So, here is what I BELIEVE your line is: 1.Qg7+ Kh2 2.f8=Q Qb5+ 3.Kh6 Qb6+ 4.Bc6!? If so, then the problem is that, from the initial position, it looks like a 12-ply search is needed to find the win. And, with three queens on the board (and the potential for a fourth in most PVs) this can take quite some time, as you have noticed. If you move ahead until after 3...Qb6+, it STILL takes CM8000 (on my more and more ancient PIII-600) over 2 1/2 minutes to find the move: Time Depth Score Positions Moves 0:00 1/3 1.82 2124 4.Kxh7 b1=Q+ 5.Kh8 Q6g6 6.Bf3 Qxg7+ 7.Qxg7 0:00 1/4 1.84 12795 4.Kxh7 b1=Q+ 5.Kh8 Q6g6 6.Qe5+ Qg3 7.Qxg3+ Kxg3 8.Qf3+ Kh4 0:00 2/5 1.72 51470 4.Kxh7 b1=Q+ 5.Kh8 Qb8 6.Bd5 Qxf8+ 7.Qxf8 Qa1+ 8.Kh7 Qa7+ 9.Kg6 Qg1+ 10.Kh6 Qg4 0:02 2/6 1.71 178789 4.Kxh7 b1=Q+ 5.Kh8 Qb8 6.Bd5 Qxf8+ 7.Qxf8 Qa1+ 8.Kh7 Qa7+ 9.Kg6 Qg1+ 10.Kh5 Qd1+ 11.Bf3 Qd4 0:08 3/7 1.72 716546 4.Kxh7 b1=Q+ 5.Kh8 Qb8 6.Bd5 Qxf8+ 7.Qxf8 Qa1+ 8.Kh7 Qa7+ 9.Kg6 Qg1+ 10.Kh5 Qg3 11.Kh6 0:18 4/8 1.71 1617792 4.Kxh7 b1=Q+ 5.Kh8 Qb8 6.Bd5 Qxf8+ 7.Qxf8 Qb2+ 8.Kg8 Qe5 9.Qf7 Qg5+ 10.Kh7 Qh4+ 11.Kg6 Qg3+ 12.Kh6 Qh4+ 13.Kg7 0:52 5/9 1.70 4681827 4.Kxh7 b1=Q+ 5.Kh8 Qb8 6.Bd5 Qxf8+ 7.Qxf8 Qb2+ 8.Kg8 Qe5 9.Qf7 Qg5+ 10.Kh7 Qh4+ 11.Kg6 Qg3+ 12.Kh6 Qh4+ 13.Kg7 Qg5+ 14.Kf8 2:38 5/9 10.63 14025528 4.Bc6 Qxc6+ 5.Kxh7 Qe4+ 6.Kh8 Qh4+ 7.Qh6 Qxh6+ 8.Qxh6+ Kg3 9.Qg7+ Kf4 10.Qxb2 Ke4 11.Kg7 Kf5 12.Qb5+ Ke6 13.Kg6 By INCREDIBLY rough estimation, I would therefore guess that it would take approximately 6-7 hours to find 4.Bc6!! from the initial position on my (slow)machine. I'll let it run overnight and find out. Good position! jm
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