The Opposition
also known as: King and Pawn vs King · Key Squares
Named after
No person — "opposition" names the geometric duel itself: kings facing off with one square between, where having to move is losing.
Origin
Understood in medieval shatranj practice; systematized across centuries of analysis into the key-square rules every textbook now states.
The story
The atom of all endgame theory. King, pawn, king: whether the pawn queens depends not on material but on a single geometric fact — when the kings stand face to face, the one who must move loses ground. From this seed grows the entire concept of zugzwang, key squares, and corresponding squares — ideas that reach their mystical extreme in positions where kings maneuver on invisible matched grids. Every player's first true endgame lesson is the shock that K+P vs K can be a DRAW, and that one tempo — one wasted pawn move hundreds of moves earlier — is the whole story. Réti's famous 1921 study (a king catching an uncatchable pawn by walking diagonally) lives in the same magic square country.
Why it matters
The foundation under everything: all pawn endgames reduce to it, and all endgames threaten to reduce to pawn endgames. Whoever counts tempi better owns the endgame — this is where counting is learned.
Notable games
- Réti's 1921 king-chase study
- Every simplification decision in every master game implicitly calculates this position