Triangulation is a tempo manipulation device used almost exclusively in king and pawn endgames. The idea is that the position would be winning if it were the opponent's turn to move, so the player with the advantage uses triangulation to "lose" a tempo and hand the move back to the opponent.
The technique works when the king can maneuver between three squares in a triangle without the opponent being able to mirror the movement. The attacking king visits three squares, returning to its starting position in three moves, while the defending king can only oscillate between two squares. After the triangulation, the defending king is forced to move first and must give ground.
Triangulation is closely related to the concept of opposition and corresponding squares. In complex pawn endgames, understanding when and how to triangulate can mean the difference between a win and a draw. This technique underscores the importance of tempo in endgame play and why king maneuvers require precise calculation.