Windmill: chess tactic
Windmill
Definition
A windmill (also called a see-saw or merry-go-round) is a tactical motif in which a series of alternating discovered checks and direct checks—most commonly carried out by a rook and bishop—forces the opponent’s king to shuttle back and forth while material is steadily harvested. Because the checked side is repeatedly obliged to parry the immediate threat to its king, it has no time to rescue the pieces that are being captured. The image of the rook “sweeping” squares in a circular motion around the immobilized king gives the tactic its picturesque name.
Typical Mechanism
- The attacking side lines up a rook and bishop so that a discovered check is available.
- When the rook moves, it gives check; when it returns, the bishop gives discovered check. The king must reply to every check, so each “turn of the blades” allows the rook to capture fresh material.
- The sequence often ends only when the attacker has taken everything of value—or has delivered mate.
Usage in Play
Spotting a potential windmill requires recognizing three ingredients:
- A pinned or poorly sheltered king that can be forced into a confined corridor (usually the back rank or the h-file).
- An aligned rook and bishop ready to alternate checks.
- Loose enemy pieces that can become targets while the king is distracted.
Players set up windmills by creating pins, opening lines, and sometimes sacrificing a minor piece to lure the king onto the “carousel.” Once the mechanism begins, calculation is relatively straightforward because the defender’s replies are forced.
Strategic & Historical Significance
Although the windmill is a tactical device, its possibility influences strategic decisions. Players may:
- Place rooks on the seventh rank and bishops on long diagonals to keep the motif in the air.
- Avoid leaving loose pieces behind a vulnerable king—especially knights on c7/f7/c2/f2 and rooks on the back rank.
- Remember famous games, such as Torre–Lasker (Moscow 1925), where a single windmill cemented Torre’s place in chess lore.
Classic Example: Torre vs. Lasker, Moscow 1925
After 24...Qd8?? the former World Champion missed the looming tactic:
Starting on move 25 the rook on d1 swings repeatedly between d7 and d8, checking and recapturing as the bishop on g2 delivers discovered checks. Lasker’s position collapses under the whirring blades.
Modern Showcase: Fischer vs. Benko, U.S. Championship 1963/64
Fischer’s 25. Bxh7+! set up a textbook windmill. Benko’s king was dragged to h7, and the American prodigy harvested pawns and pieces before calmly returning his rook to deliver mate threats. The sequence not only decided the game but became a staple in tactic textbooks.
Interesting Facts & Anecdotes
- Because the rook usually “does the harvesting,” players sometimes jokingly call it a combine harvester, turning the entire operation into agricultural imagery.
- The term windmill is older in Spanish chess literature (molino) than in English; it was popularized in the Anglosphere only after the early 20th century.
- Grandmaster Judit Polgár once commented that a windmill is “the only tactic where you get to relax while taking everything in sight; calculation ends after move two.”
- In endgame tablebases, forced mates sometimes feature windmill-like sequences lasting over 20 ply—showing that the machine can keep spinning long after we humans would have resigned.
Practical Tips
- When attacking: look for diagonal+rook batteries that can give check in two different ways.
- When defending: keep flight squares for your king and avoid aligning loose pieces behind it.
- Always calculate the entire carousel—sometimes the side performing the windmill must be ready to switch to a different plan once the checks run out.