> If a pawn moves then you can't repeat a state either, can you? So track the last 75 "moves". You are correct. So the board state from 75 moves previously pl

> If a pawn moves then you can't repeat a state either, can you? So track the last 75 "moves". You are correct. So the board state from 75 moves previously plus 75 bytes to store the last 75 moves is sufficient to store a chess game state.