Stalemate is a situation in chess whereby one player has no legal moves but is not in check (that is, his king is not attacked, but all his moves would place it under attack). Stalemate ends the game, with the result a draw. The term has since come to mean any situation where two sides have no "safe" courses of action, for instance, the position of the United States and Soviet Union during the Cold War when neither side could build defensive systems for fear of a pre-emptive attack.
With black to move, each of the four black kings shown to the right is stalemated. Stalemate is an important factor in the endgame - the set-up in the top-right of this diagram, for example, quite frequently occurs in play, and the position in the bottom-left is an example of a pawn being worth as much as a queen (even if it were white's move, there is no way to avoid this stalemate without allowing black to promote his pawn). Stalemates of this sort can often save a player from losing an apparently hopeless position.