Author: James Robertson
Date: 19:52:25 11/20/98
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On November 20, 1998 at 20:43:25, Dr. Gregor Overney wrote: >On November 20, 1998 at 00:47:46, James Robertson wrote: > >>On November 19, 1998 at 22:34:09, James B. Shearer wrote: >> >>> I was playing a Crafty clone on ICC and the following position arose: >>> >>>setboard r5k1/ppp1Q2p/1q4p1/8/8/2P1B3/bP4P1/4R1K1 b - - 0 24 >>> >>>The clone played qb6xb2 which loses quickly after be3-d4. I checked the >>>position after the game was over with crafty 15.15 on my k6-233. Crafty seems >>>to take an inordinate amount of time to reject qxb2 (over 100 seconds). Every >>>other program I have (cm5500, rebel8, rebel decade20, fritz4) either never >>>considers qxb2 or rejects it quickly (under 1 second). Is this a bug? >>> James B. Shearer >> >>Perhaps a null move problem (unlikely)? The mate is at ply 12 although Black >>should realise that it loses it's queen (even if it doesn't see the mate) by >>ply >>8. Ply 8 is when Crafty finds 1. ... c5 (after 28 seconds on my P233). GnuChess >>is another program that has problems with this position. >> >>James > >c5 on ply 8? No! c5 on ply 1 (1. ... c5)! Actually, I miscounted the plies for reasons found in my reply to Mr. Shearer's reply. It should read ply 6 a queen loss. James >My version of Crafty seems not to suggest c5 at ply 8 (but a Qd6). >If Black plays a Qxb2, Crafty finds the Bd4 for White very quickly. The >following is my Crafty 16.1 output (compiled without fastcall and therefore 15% >slower than my "old" 15.20 version): >
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