Touch-move rule the player touches his rook at the same time as touching the king, he must castle with that rook if it is legal to do so. If the player completes a two-square king move without touching a rook, the player must move the correct rook accordingly if castling on that side is legal. Otherwise, the move must be withdrawn and another king move made. When a pawn is moved to its eighth , once the player takes his hand off the pawn, a different move of the pawn can no longer be substituted. However, the move is not complete until
Fifty-move rule Fifty-move rule The fifty-move rule in chess states that a player can claim a draw if no has been made and no pawn has been moved in the last fifty moves (for this purpose a "move" consists of a player completing their turn followed by the opponent completing their turn). The purpose of this rule is to prevent a player with no chance of winning from obstinately continuing to play indefinitely , or seeking to win by tiring the opponent. All of the basic checkmates can be accomplished in well under 50 moves. However, in the 20th century it was