Author: James T. Walker
Date: 18:16:50 06/17/99
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On June 17, 1999 at 18:27:41, blass uri wrote: > >On June 17, 1999 at 17:58:22, James T. Walker wrote: ><snipped> > >>By the way Hiarcs >>turned at least one win into a draw because of the tablebases. It was a KPPKP >>endgame which is supplied with the Hiarcs CD. The problem is there is no KQPKP >>tablebase so when Hiarcs got the pawn to the 2nd rank (With Black) it did not >>know how to win the game and got stuck in 3 time rep with Mate in 7 showing in >>the window?! I had this same problem with another program which prompted a >>question a few weeks ago. Bob Hyatt says that the only way to use the >>tablebases is to have them all. I believe it but apparently some programmers do >>not. > >I do not agree that the only way to use the tablebases is to have them all. >I think that there is a bug in Hiarcs so it cannot use tablebases in an >intelligent way. > >If the evaluation does not make progress from mate in n to mate in n-1 or >shorter mate then Hiarcs should stop using the tablebases in the game that it >happens. > >I think that hiarcs can find the win by regular search after stopping using the >tablebases(at least in cases when it is mate in 7 and not mate in 40) > >Uri Hello Uri, You are right again I think. The game I mentioned was a KPPKP endgame with this setup: 8/p7/8/P7/3k2K/8/4p/8 b White just captured a bishop on g4 and black played Ke5 and announced mate in 7. After Kg6 black played a6 and announced mate in 6. Then Kg6 was followed by Ke5? (Mate in 7). They played around untill 3 time rep. A simple search without tablebases would pushed the pawn to e1=Q. But since white did not chase the pawn and instead ran away black never left the tablebase and drew the game. Any program without tablebases would have won this game easy. Jim Walker
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