Author: Dieter Buerssner
Date: 14:03:48 04/20/03
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On April 20, 2003 at 16:22:25, Sune Fischer wrote: >The releavant knowledge is relevant not only for that case but also for other >>cases. > >Maybe, maybe not (have you checked the code?). For my code, Uri is right. And I would assume it is also correct for Crafty. >I don't think anyone is highly motivated to program lots of simple 4-5 piece >specific endgames when the engine most often is used with TBs. It depends. I think, this case is somewhat special, because it happens surprisingly often in one form or the other. Also, only 4-1 TBs will help in the specific discussed case (didn't check this really ...) For example my engine does not probe 4 vs 1 - I think will in practice not help at all and sometimes hurt. >I also think there are too many exceptions to make simple rules for what is won, >drawn or lost in these endgames. Often one tempi is enough to change the >outcome, if you add general knowledge you are likely to be wrong in lots of >cases too. It depends on the specific case. With the wrong B and rook pawn, Uri had given a very good rule here in CCC about 2 years ago. For KBPK the rule would detect cases (but not all cases) where the position is a draw. I checked it against TBs, and the rule never showed draw, when it was not draw. So, in this sense, no exceptions at all. You can only do better, by following the rule. Slight generalization of the rule will easily detect the discussed position. BTW. A much easier rule will help here (and in many cases). When the opponent has only wrong color B and rook pawn(s) (and I have no knight pawn), and my K is on g1, h1, g2 or h2 (or mirrored accordingly) - I have at least a draw. No exceptions to my knowledge. In some similar cases TBs do not help. Assume doubled h-pawn + B for one side and a pawn for the other side. Without knowledge, and with currently available TBs, an engine will show high positive score for the B-side, and will refuse to take the opponent P (when it probes 4-1). Regards, Dieter
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