Author: KarinsDad
Date: 08:58:55 04/20/00
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On April 20, 2000 at 04:21:58, James Robertson wrote: >What is the current minumum number of bits required to store a chess position? >If somebody could send me instructions on how to encode a chess position in as >few bits as possible, I would be very happy. > >Thanks, >James >jrobertson@newmail.net I think the answer is around 155 or so bits with a enumeration algorithm, but I'm not sure if anyone has actually written one and proved it. The reason is that it would be a bit of a bear to write (but doable). My best is 162 bits with the algorithm I put together. It also has not been written. However, it would be quicker to calculate than an enumeration algorithm. A good algorithm is the one used in EDP. It requires 192 bits, but is extremely simple to code up. Something like: 64 64 bits bitboard 128 4 bits per piece times 32 pieces With 16 possibilites for the 4 bits, you can store the 12 standard pieces, an ep pawn (color is known based on position), a castling rook (color is known based on position), and a side to move king of each color, total 16 piece types. In fact, this can be reduced to 15 piece types since you could have 3 king pieces instead of 4; white king, black king, side to move king. KarinsDad :)
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