Author: James Flanagan
Date: 07:33:03 09/26/99
I am a relatively new user of Crafty, and am using it in the Kasparov v. World game. Our strategy seems to be to go for a draw, while GK's strategy is presumably to avoid the draw and go for a win. I've had some difficulty implementing this strategy using Crafty, which I am using through the Winboard interface. Here are two questions and observations about my recent experiences using Crafty 16.19 + all available tablebases in the Analysis Mode: 1. When the Winboard Analysis window shows an evaluation of 0.00 ... <EGTB>, I initially thought that this "guaranteed" a draw. I now come to realize (after some public embarassment) that the draw is not "forced," and either player can often bypass the draw by making a move other than the ones shown. I've tried manipulating the "contempt" function using the "drawscore -50" suggested in the crafty.doc file, but this is not always successful in bypassing avoidable draws. Any suggestions as to how I can better tune Crafty to implement the World's strategy? 2. I also found that Crafty doesn't immediately recognize draws by repetition of position by infinite check. It would seem that such a recognition function could easily be incorporated by looking for closed loops between recent positions. If these could be recognized instantly, they could be handled similarly to <EGTB> draws. 3. I am not current with the computer chess literature, but it would seem that the situation described in #1 could be handled by a type of "asymmetrical alpha/beta" approach. This approach would use different evaluation criteria for each side. (An interesting extension would be to consider the case in which the players don't have perfect knowledge of the opponent's eval functions). Does anyone know if such a system has been described theoretically, and if so has it been implemented in any current chess software? Thanks for any insight that you can share. Jim Flanagan
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