Author: Robert Hyatt
Date: 08:30:09 10/07/01
Go up one level in this thread
On October 07, 2001 at 05:21:04, Uri Blass wrote: >On October 07, 2001 at 04:57:22, Gareth McCaughan wrote: > >>Slater Wold wrote: >> >>> Here is a position from a game I played recently. >>> >>> How long does it take other engines to get this move? >>> >>> [D]8/1kbQ2NK/4p2p/8/1p1p1P2/8/4q3/8 w - - 0 1 >>> >>> Solution is Qxd4! and the game draws. >> >>Crafty 18.11, Athlon 1GHz, takes about 15 1/2 hours >>to switch from Nxe6 to Qxd4. It doesn't think it's >>drawing (eval is about -2.6). >> >>At the moment (nearly 60 hours in) it's working on >>ply 20 and doesn't have an eval or a PV yet. >>The PV at the end of ply 19 is: >> >>1. Qxd4 Qc2+ 2. Kxh6 b3 3. Nxe6 b2 >>4. Nc5+ Kc6 5. Qd7+ Kb6 6. Na4+ Qxa4 >>7. Qxa4 b1=Q 8. Qd4+ Kc6 9. Qc4+ Kd6 >>10. Qd4+ Ke6 11. Qc4+ Kd7 12. Qf7+ >>Kc8 13. Qg8+ Bd8 14. Qe6+ Kc7 15. Qe5+ >>Kd7 16. Qd5+ Ke7 17. f5 >> >>(gosh! 33 ply.) >> >>Crafty is alleged to be good at endgames, but if you're >>right that Qxd4 draws then it could clearly do with some >>improving... >> >>-- >>g > >It is clear based on the main line that Crafty has no knowledge about KQB vs KQP >endgames > >The position after 7...b1Q should be evaluated as something close to draw >because queen and bishop usually does not win against queen and here black has >queen and bishop against queen and pawn. > >Uri Nope. Never included all the special cases, just the ones that I have seen such as KR+minor + KR or KR+P. Lots of KQB vs KQP are winnable. enough that just saying "draw" would lead to embarassing results. This problem will become moot in another couple of years as more 6=piece EGTBs are done. I think it is dangerous to call KR vs KN a draw, because some are winnable, and I watched a game vs some computer on ICC last week where this came up. Crafty was in a KRP vs KBN ending and the opponent played BxP with an eval of 0.00, and crafty responded RxB with a score of mate in something. Apparently the opponent had that particular score hard-coded, and if there are exceptions, that becomes embarassing at a critical moment...
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