Author: blass uri
Date: 22:13:00 12/10/98
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On December 11, 1998 at 00:29:31, blass uri wrote: > >On December 10, 1998 at 23:22:18, Robert Hyatt wrote: > >>On December 10, 1998 at 17:11:03, blass uri wrote: >> >>> >>>On December 10, 1998 at 16:34:20, Georg Langrath wrote: >>> >>>>In the begining chesscomputers never made real sacrifices for position. Super >>>>Constellation was the first chesscomputer that was able to do that. >>>> >>>>Dear members of CCC. Have you nice examples of genuine sacrifices from your >>>>chesscomputers? They are nice to look at, and it is interesting to examine if >>>>other programs make the sacrifice. Of course all sacrifices are not healthy, but >>>>they are always nice to look at, especially from chesscomputers. >>>> >>>>Please answer this notice with sacrifices from your computers. I think we all >>>>like to examine them. >>>> >>>>Georg >>>8/4kp2/r3p1p1/2p4p/2Nb1P2/1PpP1KP1/1rP1R2P/4R3 b - - 0 1 >>> >>>This position is from mclane's tournament >>> >>>Fritz5(16 bit) played against Genius5 >>>Raa2(an impressive positional sacrifice) and Genius5 played Nxb2 and I think it >>>is the losing mistake. >>>Fritz5 can find Rc1 and I think that it is enough for doing a draw. >>> >>>Uri >> >> >> >>This really isn't a positional sacrifice at all. IE if you let crafty search >>this position it likes Rba2 to move the rook away, after 30 seconds and 13 plies >>eval is +.04... if you force it to search only Raa2, after the same depth the >>score is +.02... and from 2 plies on it doesn't think Nxb2 is the best move... >> >>So this is "just a move" and not anything spectacular, IMHO... >It is a positional sacrifice because Nxb2 is typical to computers. > >Fritz5 did not see a forced win of material after Nxb2 and I think that the same >hold for crafty. > >computers also can play Rc1 because they want to play Nxb2 next move >after Rc1 Ra7 the move Nxb2 is also a mistake. > >black can win by puting the rook at a1 and the king at a2 but this is too far to >see for computers The +.02 score after Raa2 is probably because of an improvement in the evaluation of crafty because cradty15.18 as an engine for Junior5 sees a difference of more than 0.5 pawn between Raa2 and Rba2 After Nb2 cxb2 Rb1 Bc3 crafty 15.18 evaluation is still positive(0.28 pawns for white at depth 14) Uri > >The only reason to play Raa2 is positional(black cannot lose even if black does >not choose the right plan). > >I guess that a passed pawn in the 7th rank and other positional factors were >enough for the material. > >Uri
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