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
First-move advantage in chess certain physical barriers: the "light barrier", the "quantum barrier", and the "thermodynamical barrier". These limitations imply, for example, that no computer, however constructed, will ever be able to examine the entire tree of possible move sequences of the game of chess." Nonetheless, Bremermann did not foreclose the possibility that a computer would someday be able to solve chess. He wrote, "In order to have a computer play a perfect or nearly perfect game [of chess] it will be necessary either to analyze the game completely ... or to analyze the game in an approximate way and combine this with a