Author: Tony Werten
Date: 02:48:25 05/20/04
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On May 19, 2004 at 15:40:35, Tom Likens wrote: > >Afternoon all, > >I've been reworking some of the evaluation elements of my engine >and one of the items I wanted to modify is the scoring of pinned >pieces. So with that in mind I thought I'd share some my thoughts >on the subject (and maybe obtain a few new ideas in the process). > >Currently, I'm including this items my pinned pieces evaluator. > >1. If one side is pinning a piece *and* has the right to move, then use > the SEE function to determine if the piece can be profitably captured. > >2. If a piece is "absolutely" pinned (a Nimzowitsch term) penalize it. > An absolute pinned piece can't move at all (e.g. a knight pinned to > the king by an enemy bishop would be an absolute pin, whereas > a bishop pinned to the king by a queen would not be since the bishop > could move along the diagonal of the pin). > >3. If the piece is absolutely pinned and the attacking piece's value is > less than the value of the pinned piece (regardless of who has the > move) penalize the defender a percentage of the difference between > the attacking piece and the pinned piece. > >4. If the attacker has a queen/rook, queen/bishop or rook/rook battery > attacking the pinned piece then increase the penalty. > >5. If multiple pieces are pinned increase the penalties. Also if multiple > pieces are pinned then accessed the pinned side some percentage > of the *largest* pinned piece from either 1 or 3 above. I don't think 1 and 3 should be evaluated as pinned pieces but just as hung pieces. Furthermore 3 should be adjusted. If the "pinned piece" is higher than the "pinning piece", you should evaluate the square of the "pinned on piece". (So just assume the hanging piece will move) 4 is needed to evaluate the pins correctly, and 5 won't be hit very often. Tony > >As I mentioned earlier, I'd be interested in how others handle pinned >pieces. I'd also be interested in just hearing thoughts on the above and >if I've missed anything obvious. > >cheers, >--tom
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