Endgame Theory, beginner's guide to opposition: Opposition is what we call when king and king face each other. Whoever steps in front of the enemy king first, blocks it and therefore limits the movement of their opponent. More often than not this may result in a Zugzwang situation which decides the game. Pawn promotions are most useful to illustrate the concept. In the following position, which move would you play to promote the f6 pawn? only one move wins the game for white