Author: Uri Blass
Date: 00:17:05 10/21/00
Go up one level in this thread
On October 20, 2000 at 18:55:26, Bruce Moreland wrote: >On October 20, 2000 at 16:21:13, Uri Blass wrote: > >>On October 20, 2000 at 16:00:37, Bruce Moreland wrote: >> >>>On October 20, 2000 at 15:19:32, Andreas St. wrote: >>> >>>>Hi, >>>> >>>>here a position from CSS 4/93: >>>> >>>>white: K f1 ; Q e2 ; R g1,h5 ; B c1 ; N e1 ; P a4,d3,e5,f2,h4 >>>> >>>>black: K h8 ; Q b1 ; R d8,f8 ; B b7 ; N b4,c6 ; P a6,b6,e6,f5,g7,h7 >>>> >>>> >>>>FEN: 3r1r1k/1b4pp/ppn1p3/4Pp1R/Pn5P/3P4/4QP2/1qB1NKR1 w - - 0 1 >>>> >>>> >>>>wKf1,Qe2,Ne1,Bc1,Rg1,h5,Pa4,d3,e5,f2,h4/bKh8,Qb1,Nb4,c6,Bb7,Rd8,f8,Pa6,b6,e6,f5,g7,h7 >>>> >>>>1. move: Rxh7+ >>>> >>>>Mate in 17. I think, no Program is as good as Chessmaster 6555 here. Right? >>>> >>>> >>>>Greets Andy >>> >>>This is a problem where moves by white force situations where black has very few >>>replies. You can solve this quickly by extending if black is in check and has >>>few ways out. Most programs have this extension or something similar, the >>>differences are in the degree to which they try to constrain it. >>> >>>bruce >> >>Not all of the moves of white are checks. >>The main line begins with >>1.Rh7+ Kxh7 2.Qh5+ Kg8 3.Rxg7+ Kxg7 4.Bh6+ Kh8 5.Bg5+ Kg7 6.Qh6+ Kf7 7.Qf6+ Kg8 >>8.Qg6+ Kh8 9.Bf6+ Rxf6 10.exf6 and here black is not in check. >> >>I believe that chessmaster knows to extend after 10.exf6 because of the fact >>that white threats mate in 1. >> >>Uri > >They don't all have to be checks, just almost all of them. I am surprised that >CM can find these and still operate reasonably in other cases. > >bruce I believe that CM does something more comlicated. I do not believe that it extends in every case that there is a check with few replies. If there is a long line of 36 plies with perpetual check without mate threat then it is not going to see it in less than1 second. I believe that it extends when there is a mate threat and after 10.exf6 there is a mate threat. Uri
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