I have a question in a very sorely neglected area of philosophy: that of chess! What does it mean for a move to be the "best"? Does it mean 1) It is the move that leads to the most winning variations? 2) It is the move that will most likely cause one's specific opponent to collapse? 3) The move that initiates or executes a plan of action that the player is most comfortable with? Or something else entirely?

You're right to observe that the evaluative word "best" as applied to a chess move appears to be used in many different ways. In some circumstances, the best move will be the one that ineluctably leads to checkmate of one's opponent. (Though if that move demands subsequent overwhelming calculations, there is another sense in which it's not the best. It's the best move from God's point of view -- or Deep Blue's -- but not from ours.) Often, we can't find tactical maneuvers that will promote a win and so must make a strategic move, and now the best move will be one that clearly satisfies a range of strategic goals (e.g., developing one's pieces, controlling the center, etc.). One cannot even say that "best" always involves a move that promotes a win: for instance, if one is on the ropes, the best move will be the one that increases one's prospects for a draw. A philosophical issue is broached if one asks whether there is something in common to all these uses of the word "best". Some philosophers...