Mined Squares: The Zugzwang Trap in Pawn Endgames

Watch the method: press play to see the winning idea run, or step through it move by move.

Some squares in pawn endings are booby-trapped. Occupying them is not wrong because of what they attack or defend, but because of WHOSE MOVE it becomes once both kings take their posts. They are called mined squares, and defusing them is pure move-counting.

The mechanism. With pawns fixed on e5 and e6, the natural attacking square f6 and the answering square d5 form a pair. If the kings land on them with the attacker to move, the attacker is not merely drawn, he is lost; with the defender to move, the position collapses. Neither square is good or bad in itself. What matters is arriving second.

The technique is the sidestep. Instead of marching straight onto the mined square, the winning king takes an adjacent route that keeps the entry available as a THREAT. The defender, with less space, cannot mirror the wait: sooner or later he must commit to his square first, and then the attacker steps in with the move in his pocket.

In this drill exactly one first move wins and the plausible straight approach throws the win away instantly. It is the cleanest possible introduction to reciprocal zugzwang, and the gateway to the full corresponding-squares method.