Touch-move rule move or capture the first of the pieces that they touched. If it cannot be determined whether he touched his own piece or the opponent's piece first, it is assumed that he touched his own piece first. If a player touches more than one piece, he must move or capture the first piece that can be legally moved or captured. An exception to that is an attempted illegal castling; in that case the king must be moved if possible, but otherwise there is no requirement to move the rook. When castling, the king must be the first piece touched. If
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