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
Candidate move simply not capable of performing the complex pattern recognition that was required to find appropriate candidate moves, and that it was easier to have computers perform simple exhaustive searches. Today, most chess programs still rely mainly on brute-force searches, but as search algorithms have improved, today's chess engines seem more and more to be using candidate moves in their analysis. Hydra, for example, is widely considered to be a "Type B" (candidate move finding) computer. Candidate move In abstract strategy board games, candidate moves are moves which, upon initial observation of the position, seem to warrant further analysis. Although in