'Losing move': an information processing concept

Chess, like all games of perfect information, is, from a game-theoretic point of view, trivial. The value of the game, as well as optimal strategies, can be calculated - in principle, of course - by minimaxing backwards from terminal positions. If, as generally believed, the game's value is <u>Drawn</u>, then it is possible for a player to make a losing move - one that changes the value from D to L - but not to make a winning move - one that changes the value from D to W. (W, D and L mean 'won', 'drawn', and 'lost' from the standpoint of the player in question.)