Author: Bruce Moreland
Date: 00:24:54 05/12/98
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On May 12, 1998 at 01:17:08, Kai Skibbe wrote: >WKh3, Rh6, Pg3,g2 >BKc5, Rb6, Ph7 >White to move >Why is this position so difficult for programs ? Thanks for this position, it was a lot of fun. The reason it is hard is that after the rook exchange, if white just goes straight for the pawns, it is a draw. This K+P ending is trickier than it looks. 1. Rxb6 Kxb6 2. Kh4 is drawn after 2. ... Kc5. 1. Rxb6 Kxb6 2. Kg5 wins I believe, but 2. ... Kc5 3. Kg5? is drawn after 3. ... Kd4. The correct move seems to be 3. Kf4! (box), with a big fail high. I think everything else draws in this case. 1. Rxb6 Kxb6 2. g4 also wins after 2. ... Kc5 3. Kg3! (box) Kd4 4. Kf4! (box). In these endings, black gets to hang onto his h7 pawn for a while, so these programs are choosing 1. Rxh7 because they'd rather be two pawns up in a R+P ending than one pawn up in a K+P ending. If the K+P ending were easier, they'd all go for it. In my estimation, this is a judgement call on the part of the program. I think that tweaking a program so that it solves this might be a mistake. bruce
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