Author: Uri Blass
Date: 03:19:40 11/05/02
Go up one level in this thread
On November 05, 2002 at 05:34:41, Joachim Rang wrote: >On November 05, 2002 at 02:37:11, Uri Blass wrote: > >>On November 04, 2002 at 21:33:36, Rob Shultz wrote: >> >>>Shredder 6.02 comes up with the following line: >>> >>>New game >>>1k6/8/8/8/8/5p1p/PPP5/6K1 w - - 0 1 >>> >>>Analysis by Shredder 6.02: >>>1.b4 Kc7 2.a4 Kc6 3.a5 Kb5 4.c3 Ka6 5.c4 h2+ 6.Kxh2 f2 7.Kg2 f1Q+ 8.Kxf1 Kb7 >>> +- (15.67) Depth: 30/42 00:14:47 844201kN, tb=4168129 >>> >>>(Shultz, Delmont 04.11.2002) >>> >>> >>> >>>New game >>>1k6/8/8/8/8/5p1p/PPP5/6K1 w - - 0 1 >>> >>>Analysis by Hiarcs 8: >>> -+ (-1.70) Depth: 20/44 00:10:16 151098kN, tb=296590 >>>1.a4 Kb7 >>> -+ (-1.95) Depth: 21/48 00:12:20 180842kN, tb=354248 >>>1.a4 Kb7 2.b4 Ka7 3.b5 Kb6 4.c4 Kb7 5.a5 Kc7 6.a6 Kb6 7.c5+ Ka7 8.c6 Kb6 9.c7 >>>Kxc7 10.a7 Kb7 11.b6 Ka8 12.Kf1 h2 13.Kf2 h1Q >>> -+ (-7.27) Depth: 21/48 00:16:40 250066kN, tb=457173 >>> >>>(Shultz, Delmont 04.11.2002) >> >>Can you play a game between shredder and Hiarcs8 and post moves+evaluations? >> >>Uri > > >that's not necessary: That is necessary to see when Shredder understands that white is lost. > >white is lost because he can't move his king, but the black king can stop all >three connected passed pawns from white (!), because white neither can support >its pawns with his king nor can put black into zugzwang (it is white who will be >in zugzwang). White is forced to move its pawns forward until black will have >all eaten them and then has to move its king which looses. > >This is another one of Eduards famous zugzwang-problems which are for most >engines very hard. Congratulations! zugzwang is usually no problem in pawn endgame because engines do not use null move pruing in pawn endgames. I was interested to know what wrong pruning shredder use in pawn endgame and I am surprised if it is simple null move pruning. I expected mistakes by some special pruning algorithm for pawn endgames so I thought that we can discover details about it by finding when it fails. Uri
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