What Is a Windmill in Chess?

Definition

A windmill — sometimes called a see-saw — is a devastating pattern where a rook and bishop combine to produce discovered check after discovered check. The rook checks, the king is forced to respond, the rook swings back capturing material with another discovered check, and the cycle repeats. Because the defender must answer each check, they can only watch as their position is stripped bare.

Example

A rook on g7 supported by a bishop on the long diagonal moves away with discovered check, forcing the king to h8. The rook returns to g7 with check, capturing whatever sits there on the way — and the process repeats along the seventh rank.

How to spot it

• You need a rook deep in enemy territory plus a bishop giving the discovered check behind it.
• The enemy king must be confined so it shuttles between two squares.
• Count the material you can collect before the cycle runs out.
• The most famous example is Torre against Lasker, Moscow 1925.

The mistake most players make

Breaking the cycle too early to grab a piece without check. The whole point is that every move is forcing — the moment you give the defender a free move, the windmill stops.

Related terms

• Discovered check — A discovered check is a discovered attack where the unveiled piece gives check, forcing an immediate response.
• Discovered attack — A discovered attack is when moving one piece unveils an attack from a long-range piece behind it.
• Battery — A battery is two or more long-range pieces stacked on the same line so their power combines.
• Initiative — The initiative is being the player making threats while your opponent is forced to react.