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 Otherwise, the move must be withdrawn and another king move made.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
Late Move Reductions lead to a different search space than the pure alpha-beta method which can give different results. Care must be taken to select the reduction criteria or the search will miss some deep threats. Late Move Reductions In computer chess, and in other games that computers play, Late Move Reductions (LMR) is a non-game specific enhancement to the alpha-beta algorithm and its variants which attempts to examine a game search tree more efficiently. It uses the assumption that good game-specific move ordering causes a program to search the most likely moves early. If a cut-off is going to happen in a