Author: Terry McCracken
Date: 23:02:24 04/07/02
Go up one level in this thread
On April 07, 2002 at 23:59:14, Terry McCracken wrote: >On April 07, 2002 at 17:51:40, martin fierz wrote: > >>On April 07, 2002 at 17:22:03, Dieter Buerssner wrote: >> >>>On April 07, 2002 at 15:48:22, Terry McCracken wrote: >>> >>>>Here's an Endgame that should make _all_ chess engines really work! >>> >>>[3n2k1/p2P2p1/1p6/7Q/5q1P/8/PP6/1K6 w - -] >>> >>> >>>>Fritz 7 sees the draw but doesn't understand the loss after 1.Qe8+..Qf8?? >>>> >>>>Played by Mieses-NN 1903. Mieses won after Qf8??, I'll give the main line. >>>> >>>> >>>>1.Qe8+ Qf8 2.h5 Nf7 3.Kc2 Nd8 4.Kc3 Nf7 5.a4 Nd8 6.Kc4 Nf7 7.Kd5 Nd8 8.b4 Nf7 >>>>9.Kc6 Nd8+ 10.Kc7 Line >>> >>>Which would be the winning line after 2...b5. My engine unfortunately fails to >>>see it ... >>> >>>You give Qf8 a "??". Should it be really obvious, that tis is a bad move? >>> >>>Regards, >>>Dieter >> >>hi dieter, >> >>yes, it is obvious that this is a bad move. the point is something which >>computers are worst at, an "eternal bind". after 1. ...Qf8 2.h5, no black piece >>can move any more: if the king moves, black loses the queen, the queen cannot >>move, because it's illegal, and so the only thing to do is to shuffle the knight >>back and forth, because if you move it away, you lose to d8Q. so all you have to >>see is that after 2.h5 black can only move the knight, and white can move the >>king right down to c7. ...g6 at any time is met by h6-h7-h8 winning. for a >>human, this is really easy - we recognize the fact that black is reduced to >>shuffling and can ask ourselves: where would i like my king to be - i don't have >>to calculate anything! a computer would have to see through the whole line until >>the knight is lost. which is quite deep... >>this type of bind is causing me headaches in my checkers program, and it is a >>very general class of positions where chess programs are weak at too. >> >>aloha >> martin > >You described it best Martin, with "Eternal Bind", and your quite correct this >position is fairly easy for experienced players, not computers and a true >"Nightmare" for chess programmers! > >It would be interesting how Deeper Blue would have tackled this position! It may >have been able to search far enough. > > >As for your checker programme maybe http://games.cs.ualberta.ca/~chinook/book/ >could help? > >I have a friend near Ottawa, Martin Devenport who knows Jonathan Schaeffer, and >have been friends since 1971. Both are chessmasters as well. However I don't >know Jonathan Schaeffer. > >Maybe when I catch Martin online if I remember...I'll ask him about Jonathan and >Chinook, maybe he can ask him about specific programming techniques, that could >help you. > >I can't promise anything, but I'll ask anyways. If I remember?:o) > >Regards, > Terry Opps! I just checked your website and you're very familar with Jonathan's work!:)
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