What Is a Windmill in Chess?
A repeating cycle of discovered check + regular check that harvests enemy material each rotation while the king oscillates helplessly between two squares. The four rules, the Torre vs Lasker Moscow 1925 birth-game, six famous windmills from Adams 1920 to Karpov 1985. No signup. No paywall.
TL;DR — Windmill in 5 Bullets
- A windmill (or seesaw) is a repeating discovered-check cycle — a battery fires the same discovered check over and over, harvesting one enemy piece per rotation.
- The enemy king oscillates between exactly two squares — every rotation forces it to the flight square, then the return check forces it back.
- Every windmill needs a discovered-check battery — a bishop or knight in front of a rook or queen along a shared line to the enemy king.
- Count the harvest before firing — if the projected material gain (usually queen + minor + pawns) exceeds the setup sacrifice (often a queen), spin the windmill. Otherwise keep looking.
- Textbook examples: Torre vs Lasker Moscow 1925 (the archetypal windmill), Adams vs Torre New Orleans 1920 (the earlier proto-windmill), Alekhine vs Bogoljubov Hastings 1922, Fischer vs Benko US Championship 1963/64.
What Is a Windmill?
A windmill is a repeating tactical cycle where a discovered-check battery fires the same combination of moves over and over. On each rotation, a friendly bishop or knight moves off a shared line to reveal a discovered check from a friendly rook or queen behind it — and in the same move, captures an enemy piece on the new square. The enemy king MUST move (chess law), and the only legal square is a single flight square you engineered before the windmill began. Then the moved front piece delivers a direct check from the capture square, forcing the king back to its starting square, where the discovered check can be repeated on a fresh enemy piece one square further along the line.
The pattern spins like a windmill's blades — hence the English name — and the older English name 'the seesaw' captures the same idea from the enemy king's perspective (two squares, back and forth). German calls it 'Mühle' (mill), Russian calls it 'мельница' (mel'nitsa, mill). Every major chess-language canon has a single word for this pattern, which reflects how universally recognisable it is once you know the setup.
Windmills connect to every other tactical motif. Every windmill is a battery (specifically a discovered-check battery aimed at the enemy king) firing repeatedly; every windmill uses a discovered attack (specifically a discovered check) as its atomic move; and some windmills fire double check on one or more rotations — the most devastating variant because blocking is impossible. Related terminology hubs: sacrifice, fork, and pin.
The Four Rules That Define a Windmill
Every windmill obeys the same four structural rules. Learn these once and every windmill on every board becomes instantly recognisable:
Rule 1 — A windmill is a repeating cycle, not a single move
Every windmill consists of TWO alternating checks fired from the same battery over and over: a discovered check that opens the line and grabs enemy material on the moved-away square, followed by a regular check from the moved piece that forces the king back to its original square, where the discovered check can be repeated. The pattern spins like a windmill's blades — each rotation harvests one more enemy piece or pawn while the enemy king oscillates helplessly between exactly two squares. A single discovered check is not a windmill; a windmill is the CYCLE.
Rule 2 — The king is trapped between two squares
The victim king can move to exactly one flight square when the discovered check fires, and only back to its starting square when the moved piece then checks directly. Every other escape route is blocked by friendly pieces, board edges, or attacking coverage. This two-square oscillation is the STRUCTURAL prerequisite — before you play the first move of a windmill, verify the king has no third escape square, otherwise the cycle breaks after one turn.
Rule 3 — The moved piece harvests material each rotation
The piece that fires the discovered check (typically a bishop or knight) captures a different enemy piece on the same rank / file / diagonal each iteration. The queen, rook, or minor piece that gets picked up is on a square that was previously safe — the check dictates the recapturing sequence, so the defender cannot recapture without leaving the king in check. Every rotation nets one piece (or one pawn in a pure-pawn-harvest windmill) with zero material given back.
Rule 4 — The back piece (the 'gun') stays fixed
The piece firing the discovered check — usually a rook or queen behind the moving bishop — stays put on its line and provides the check each time the front piece moves off. The battery is the ENGINE of the windmill: without a rook or queen on the same file, rank, or diagonal as the enemy king, no discovered check is possible and there is no windmill. This is why every windmill in the historical canon starts with a bishop or knight in front of a rook or queen, all aimed at the enemy king along a single line — the same structural setup as a discovered-check battery, but designed to fire repeatedly rather than just once.
How the Windmill Spins — Move by Move
The mechanics are the same across every windmill in the historical canon. Four stages, repeated until the harvest is exhausted or a mating shot becomes stronger:
The setup — battery aimed at the enemy king
Before a windmill can spin, you need three ingredients on the board simultaneously: (a) a friendly bishop or knight positioned between a friendly rook or queen and the enemy king along a shared file, rank, or diagonal (the discovered-check battery); (b) an enemy king trapped in a two-square corridor with no third escape square available (usually the corner or edge of the board, often after being drawn there by a queen sacrifice); (c) enemy pieces stationed on the file, rank, or diagonal where the moving front piece can capture them one by one. Torre vs Lasker Moscow 1925 assembled all three ingredients over 24 moves before firing the first cycle on move 25.
The first rotation — discovered check + capture
The front piece (bishop or knight) moves off the shared line, revealing the discovered check from the rook or queen behind. In the same move, the front piece captures an enemy piece on its new square — this is the harvest. The enemy king MUST respond to the check (chess law), and the only legal square is the flight square you engineered before the windmill began. The enemy loses one piece and moves the king one square. Net: +1 piece for the attacker, king relocated to the flight square.
The return check — moved piece attacks the king back
The front piece (now on the capture square) delivers a direct check to the enemy king on the flight square. The only legal response is to move the king back to its starting square, because every other square is either attacked, blocked, or covered by the fixed back piece. The king oscillates back — same square it started on before the first check. This second half of the rotation completes the 'seesaw' motion that gave the windmill its second-most-common name (English writers, especially before World War II, called it 'the seesaw' interchangeably with 'the windmill').
Repeat until the harvest ends
Steps 2 and 3 repeat as long as there are enemy pieces on the front piece's shared line to capture. Each rotation harvests one piece, then the front piece returns and re-fires the discovered check on a fresh enemy piece one square further along the line. The cycle ends when either (a) no enemy pieces remain on the line, (b) an enemy piece defends the flight square or blocks the shared line, or (c) the attacker chooses to finish with a mating shot rather than another capture. Torre's windmill against Lasker executed FIVE rotations in a row — bishop capture on g7, king to h8, bishop check with the rook firing behind, king to g7, bishop capture on b7, king to h8, and so on — netting a queen and multiple pawns before Torre resigned the windmill and converted a winning endgame.
Six Famous Windmills from Chess History
The windmill has decided textbook combinations, exhibition games, and world-championship match games from 1920 to 1985. Every one is worth stepping through in a free PGN viewer:
Torre vs Lasker — Moscow 1925 (the birth of the windmill)
The archetypal windmill and the game every subsequent explanation cites. Carlos Torre Repetto, a 20-year-old Mexican grandmaster, played 25.Bf6!! against former world champion Emanuel Lasker in the Moscow International tournament. The queen sacrifice drew Lasker's queen off its defensive square; then 26.Rxg7+ Kh8 27.Rxb7+ Kg8 28.Rg7+ Kh8 29.Rxa7+ Kg8 30.Rg7+ Kh8 31.Rg5+ spun the seesaw for five rotations, harvesting Lasker's queen, bishop, and multiple pawns for the price of Torre's queen. Lasker resigned twelve moves later. The game is annotated in every chess-history book and every 1400-level tactics manual — 'Torre's windmill' has entered chess vocabulary as the name of the pattern itself in many languages.
Adams vs Torre — New Orleans 1920 ('Sarasota Windmill')
Predates the Torre–Lasker game by five years but is less-famous because it happened in a casual match rather than a top-tier tournament. Edwin Adams's ...Qe2!! set up a queen-behind-rook battery on the e-file against Torre's king; when Torre took the queen with 24.Rxe2, Adams's rook on e8 fired a discovered check while capturing a piece with each rotation of the swap sequence. The game shows that the windmill pattern was recognised in club circles a decade before Torre's Moscow demonstration made it globally famous. Adams's game appears in Reinfeld's 1955 collection The Human Side of Chess as example #62 with the annotation 'the first documented windmill in serious American play'.
Alekhine vs Bogoljubov — Hastings 1922
Alekhine's blistering exhibition attack finished with a three-rotation windmill on the g-file: 34.Bh6+! Kh8 35.Bxg7+ Kg8 36.Bh6+ Kh8 37.Bxf8 with the queen firing the discovered check each time from g6. Bogoljubov lost the rook on f8 and both kingside pawns before the windmill's terminal rotation set up a mating net. Alekhine annotated the game in his 1927 book My Best Games of Chess 1908–1923 as 'the cleanest windmill I have ever played' — the only game from his own collection where he used the term 'windmill' rather than the more common German 'Mühle'. The pattern is worth memorising because it demonstrates the bishop-plus-queen battery variant rather than the more common bishop-plus-rook Torre setup.
Fischer vs Benko — US Championship 1963/64 (partial windmill)
Bobby Fischer's 19.Rf6!! set up a bishop-plus-rook windmill against Pal Benko's kingside-castled king. The full seesaw only executed two rotations before Fischer switched to a direct mating attack, but the setup was pure textbook: bishop on the b1–h7 diagonal firing the discovered check, rook on the sixth rank checking directly. Fischer wrote in his 1969 book My 60 Memorable Games (game #33) that he had studied Torre–Lasker as a boy and consciously used the same pattern-recognition — 'I saw the windmill was on the board before I saw the mate, and mate was faster'. The game is a case study in when to STOP a windmill: Fischer harvested one pawn and one exchange, then switched to Qxh7# rather than continuing the seesaw.
Alekhine vs Freeman — New York simul 1924
One of Alekhine's most-quoted simultaneous-exhibition games, played the year before Torre–Lasker. Alekhine's Bg5+! opened a bishop-plus-queen windmill against Freeman's cornered king on h8, netting three minor pieces in four rotations before finishing with Qxh7#. Alekhine gave this game as example #3 in his 1932 lecture 'The Windmill in Practical Play' (transcribed in his collected essays), specifically to make the point that windmills can be pre-computed at the board — 'the pattern is unmistakable once the enemy king is in the corner and a bishop or knight can fire a discovered check on a rook or queen'. Alekhine's insistence on the term 'windmill' rather than the older German 'Mühle' helped standardise the English name.
Karpov vs Kasparov — WC 1985 Game 16 (defensive windmill)
The rare defensive windmill. Karpov's 24.Nxc7+! set up a knight-plus-rook battery firing discovered checks against Kasparov's queen every rotation, harvesting a pawn and a tempo each time — enough to force an escape into a drawable endgame from what looked like a losing middlegame. Kasparov annotated this game in his 2003 collection My Great Predecessors Vol 5 as 'the only defensive windmill I have ever met in a serious game' — most windmills are attacking cycles, but Karpov demonstrated that the discovered-check battery mechanism can also be spun in a defensive role to gain tempi and disrupt an opponent's attacking plan. The game is worth studying to understand that windmills are not exclusively winning combinations — a defender can spin one too.
How to Spot a Windmill at the Board — Four Steps
Every windmill is spottable with the same four structural tests. Run all four every time an enemy king reaches a corner or edge with a battery aimed at it:
Step 1 — Check for a discovered-check battery
The first structural test: is there a friendly rook or queen aimed at the enemy king along a file, rank, or diagonal, with a friendly bishop or knight standing between them? If yes, you may have the ENGINE of a windmill on the board. If no, no windmill is possible. Scan every rook and queen line to the enemy king every move — this is the same scan you already do for discovered attacks, so it costs zero additional tempo at the board.
Step 2 — Check for a king trapped in a two-square corridor
The second structural test: does the enemy king have EXACTLY ONE flight square when the discovered check fires? If two or more squares are available, the seesaw breaks after one turn. If none, the discovered check is mate on the spot (which is a bigger dividend than a windmill, so play it). Only exactly one flight square supports a spinning windmill. The king is usually in the corner (h8, a8, h1, a1) or on the second-to-last rank with the pawn shield still intact.
Step 3 — Count the harvest
The third scoring test: how many enemy pieces does the front piece pass through on its way back and forth? The bishop or knight will capture one piece per rotation on its capture square, then move back and capture another one on the next rotation. Multiply pieces captured × their average value = the total harvest. If the total exceeds the value of what you'll sacrifice to set up the windmill (usually a queen — see Torre–Lasker), fire the windmill. If not, keep looking for a better shot.
Step 4 — Confirm the return check is legal
The fourth structural test: does the front piece attack the enemy king from its capture square? If not, the windmill breaks after the first rotation — the enemy king would not be forced back to its starting square. Every rotation of a windmill requires that the front piece delivers a legitimate direct check from every capture square along the shared line. If any single square in the line does NOT support a return check, the windmill stops there.
How to Defend Against a Windmill — Four Answers
When your opponent points a discovered-check battery at your cornered king, four defensive tactics disarm the windmill. Combine two or three and even the strongest seesaw stops spinning:
Prevent the setup — never castle into a corner with a battery aimed at you
The strongest defensive answer is not to enter the windmill zone in the first place. When your opponent has a queen or rook on the same diagonal, file, or rank as your king with a bishop or knight ready to jump between them, DO NOT allow the king to reach the two-square corner where a windmill can spin. Castle to the other wing, delay castling, or evacuate the king to a square where the discovered-check battery no longer aims at it. Prophylaxis is the #1 defensive plan against a windmill setup.
Break the two-square corridor
If the setup is already on the board, disrupt the two-square oscillation by creating a THIRD escape square for the king. A friendly pawn pushed to give the king a flight square (g6 for a Black king on g8/h8, h6 for the same king, g7 to break a windmill on the sixth rank), a friendly piece dropped to guard the flight square, or a piece traded off the king's escape route all break the seesaw geometry. The moment the king has TWO flight squares instead of one, the windmill degenerates to a normal discovered-check attack — still bad, but not catastrophic.
Block the shared line with a defender
Insert a friendly piece between the enemy back-piece (the gun) and your king on the shared line. If the line is blocked, no discovered check is possible, and no windmill can spin. This is the classic 'interposition' defence — a knight or bishop dropped onto the shared line, defended by a pawn or another piece, converts the windmill setup back into a harmless middlegame. Torre vs Lasker featured no such interposition because Lasker's queen had already been drawn off by 25.Bf6!!; had Lasker's queen still been on the board with Qe7 as a possible defensive move, Torre's windmill would have been prevented.
Counter-sacrifice to disrupt the battery
The desperate defence. If none of the prophylactic answers work, sacrifice material — usually a rook or bishop — to remove the front piece of the discovered-check battery or the back piece firing behind it. The material loss is worth it if it prevents a much larger harvest from a spinning windmill. Karpov defended a threatened windmill against Timman in 1988 by sacrificing a full rook to remove the bishop-front-piece — the resulting endgame was two pawns down but drawable, whereas the windmill would have won three pieces and the game. Every strong defender considers the counter-sacrifice before conceding the windmill.
Windmill vs Related Tactics
Four concepts are frequently confused — windmill, discovered check, double check, and perpetual check. Each has its own structural test and different consequences:
| Concept | Definition | Key idea | Example |
|---|---|---|---|
| Windmill | Repeating cycle of discovered check + direct check harvesting material each rotation | Two-square king oscillation + fixed back piece firing discovered check each turn | Torre vs Lasker Moscow 1925 |
| Discovered check | One-time move where the moved piece unmasks a check from a piece behind it | Single check, no cycle | Réti vs Tartakower Vienna 1918 |
| Double check | Discovered check where BOTH the moved and revealed piece deliver check simultaneously | Blocking and capturing both impossible; king MUST move | Philidor's Legacy 1749 smothered mate |
| Perpetual check | Repeating check cycle where the attacker cannot force mate but the defender cannot escape | Draw by threefold repetition; NO material harvest | Any king-and-queen vs king-and-lone-piece drawn ending |
For the full guides on the related concepts, see What Is a Discovered Attack in Chess?, What Is a Double Check in Chess?, and What Is a Battery in Chess?
Common Beginner Mistakes
The same five windmill errors appear at every rating level below 2000. The fixes are mechanical — learn them once and every windmill you try in your next twenty games converts:
Firing a windmill without a two-square corridor
If the enemy king has two or more flight squares when the discovered check fires, the seesaw breaks after one rotation. Before the first move, physically trace the king's legal squares — if more than one is available, the windmill cannot spin. The #1 club-level windmill mistake is confusing 'discovered check available' with 'windmill available' — every windmill is a discovered check, but not every discovered check is a windmill.
Not counting the harvest before sacrificing to set up the windmill
Torre sacrificed his queen (9 points) to spin his windmill; the harvest was Lasker's queen (9), bishop (3), and multiple pawns (~4) = 16 points, netting +7. If the pre-computed harvest doesn't exceed the setup sacrifice, don't play the windmill — it will lose material overall. Every windmill decision is arithmetic: setup cost vs projected harvest, and the harvest must be larger.
Confusing a windmill with perpetual check
A windmill HARVESTS material each rotation and typically ends with a mating shot or a winning material advantage; perpetual check DRAWS by threefold repetition without gaining any material. The two look similar (both involve repeating check cycles) but the outcomes are opposite. If the front piece has nothing to capture on any of its rotation squares, you have perpetual check (a draw), not a windmill (a win).
Missing the return check that keeps the windmill spinning
The moved front piece MUST deliver a return check from the capture square to force the king back. If the front piece cannot check from the capture square, the enemy king has two options on that turn (move anywhere legal, or capture the checker), and the windmill stops. Trace both halves of every rotation before firing — the discovered check AND the return direct check must both be legal for the seesaw to continue.
Ignoring defensive resources during the windmill
Every rotation gives the defender a chance to interpose a piece on the shared line, block the flight square, or counter-sacrifice. A defender who spots the windmill mid-cycle can often stop it with a rook interposition or a knight sacrifice. Don't assume the windmill will play itself — verify each rotation after the actual position, not the pre-computed one. In blitz especially, the defender often finds a resource the attacker missed at rotation 3 or 4.
Practise Windmills for Free
Windmills are the most memorable of all tactical patterns because the visual — the enemy king oscillating between two squares while a rook and bishop harvest material — is instantly recognisable. Three free, no-signup ways to train:
- What Is a Discovered Attack in Chess? — the atomic mechanism every windmill uses.
- Free PGN Viewer — step through Torre vs Lasker Moscow 1925 (the archetypal windmill), Adams vs Torre New Orleans 1920 (the earlier proto-windmill), Alekhine vs Bogoljubov Hastings 1922 (three rotations on the g-file), and Fischer vs Benko US Championship 1963/64 (two rotations before Fischer switched to mate).
- chess.rodeo — no account, no paywall — play live games and let Stockfish flag every 'windmill available' opportunity in the post-game review. Every game with a discovered-check battery aimed at a cornered king gets a note if the seesaw rotation was missed.
Frequently asked questions
Everything intermediate players ask about the windmill — definition, why it's called a windmill, the four rules, Torre vs Lasker 1925, how to spot one, how to defend against one, the German name Mühle, and where to practise for free.
What is a windmill in chess?
A windmill (also called a seesaw) is a repeating tactical cycle where a discovered-check battery fires the same combination of moves over and over — the front piece captures an enemy piece and moves off the shared line, revealing a discovered check from a rook or queen behind; the enemy king moves to its one flight square; the front piece delivers a direct check on the flight square, forcing the king back; and the cycle repeats on a fresh enemy piece each rotation. The front piece harvests one enemy piece or pawn per rotation while the enemy king oscillates helplessly between exactly two squares. The archetypal windmill is Torre vs Lasker Moscow 1925 (a bishop-plus-rook windmill on the seventh rank harvesting Lasker's queen, bishop, and multiple pawns after Torre's 25.Bf6!! queen sacrifice).
Why is it called a windmill?
The pattern spins like a windmill's blades — each rotation of the front piece brings it back to its starting square before firing again in the same direction, just like a windmill blade returning to its top position on every turn of the axle. The English name 'windmill' became standard in the 1920s after Torre's Moscow 1925 game was published worldwide with the term in Russian, English, and German chess magazines. Older English writers (especially before 1930) also called it 'the seesaw' — because the enemy king seesaws between exactly two squares each rotation — and the two terms remain interchangeable in modern chess literature.
What is the difference between a windmill and a discovered check?
A discovered check is a SINGLE move where a friendly piece moves off a shared line to unmask a check from a piece behind it. A windmill is a REPEATING CYCLE of discovered checks — the same battery fires the same discovered check over and over, harvesting material each rotation. Every windmill is built from discovered checks, but not every discovered check is a windmill — the windmill requires the two-square king corridor and the repeated harvest. Think of the discovered check as the ATOMIC MOVE and the windmill as the SEQUENCE built from repeated firings. See our /blog/what-is-a-discovered-attack hub for the full guide on the underlying mechanism.
What is Torre vs Lasker Moscow 1925?
Torre vs Lasker Moscow 1925 is the archetypal windmill game and the reason the pattern has 'Torre's windmill' as an alternate name in many languages. 20-year-old Carlos Torre Repetto played 25.Bf6!! against former world champion Emanuel Lasker, drawing Lasker's queen off with the sacrifice. Torre then spun a five-rotation windmill (bishop on g7 firing the discovered check, rook on the seventh rank checking directly each return) that harvested Lasker's queen, bishop, and multiple pawns. Lasker resigned twelve moves later. The game appears in every chess-history book, every 1400-level tactics manual, and every YouTube 'best combinations of all time' compilation. It is the single most-cited game for teaching the windmill pattern.
How do you spot a windmill at the board?
Four structural tests: (1) Is there a friendly discovered-check battery aimed at the enemy king — a bishop or knight in front of a rook or queen along a shared file, rank, or diagonal? (2) Is the enemy king trapped in a two-square corridor with exactly ONE flight square when the discovered check fires? (3) Does the front piece pass through enemy pieces on its capture line, so each rotation harvests material? (4) Does the front piece deliver a direct check from the capture square, forcing the king back to its starting square? If all four tests are YES, you have a windmill. If any test fails, you may still have a valuable discovered-check tactic but not the spinning cycle.
How do you defend against a windmill?
Four defensive answers: (1) PREVENT the setup by never castling into a corner with a battery aimed at your king — prophylaxis is the #1 defence. (2) BREAK the two-square corridor by pushing a pawn or dropping a piece to give the king a third escape square, degenerating the windmill to a normal discovered attack. (3) BLOCK the shared line with a defender (knight preferred, hard to trade) between the back piece and your king. (4) COUNTER-SACRIFICE — give up a rook or bishop to remove the front piece of the battery or the back piece firing behind it, preventing a much larger harvest. Combine 2–3 of these responses and even the strongest windmill loses its firing plan.
Is a windmill the same as perpetual check?
No — the two look similar (both involve repeating check cycles) but the outcomes are opposite. A WINDMILL harvests one enemy piece per rotation and typically ends with a winning material advantage or a mating shot. A PERPETUAL CHECK draws by threefold repetition and gains no material. The structural difference: in a windmill, the front piece captures a different enemy piece on each rotation; in perpetual check, no captures happen — the checker just alternates between the same handful of squares forever. If your rotations capture pieces, you have a windmill (win); if they don't, you have perpetual check (draw).
Can pawns be part of a windmill?
Pawns rarely trigger a windmill because their single-square capture range is too short to keep firing a discovered-check battery over multiple rotations — a pawn can move off the shared line ONCE, then it's gone. But pawns can be the HARVEST (captured by the moving bishop or knight each rotation) and pawns can also break a windmill's two-square corridor (a pawn push to give the king a third escape square is the #1 defensive answer). Torre vs Lasker Moscow 1925 harvested three pawns during the windmill; every windmill textbook counts pawn captures alongside piece captures when scoring the total harvest.
What is the difference between a windmill and a battery?
A battery is the STATIC SETUP — two or more friendly pieces stacked on a shared line ready to fire. A windmill is the DYNAMIC SEQUENCE — the same battery firing a discovered check repeatedly over multiple turns. Every windmill USES a battery (specifically a discovered-check battery aimed at the enemy king), but not every battery leads to a windmill — most batteries fire once and finish the attack with a direct capture or mate. The windmill is the special sub-case where the battery fires the SAME discovered-check pattern over and over. See our /blog/what-is-a-battery-in-chess hub for the full guide on the setup mechanism.
Do windmills happen at grandmaster level?
Yes but rarely at classical time controls — a windmill setup is very concrete pattern-recognition, so both sides usually see it coming and the defender prevents the setup 4–6 moves before it materialises. Windmills DO appear frequently in (a) simultaneous exhibitions (Alekhine's simul games contain at least six windmills that grandmaster opponents would have prevented in tournament play); (b) blitz and bullet games where the defender misses the setup; (c) computer-vs-human matches from the 1990s where the human missed the pattern; and (d) engine games where one side deliberately provokes a windmill because the defensive resources are inadequate. In classical tournament play at 2600+, a full windmill happens maybe once every 500 games — but 'partial' windmills (two rotations before the defender finds a resource) are common enough that every top player studies the pattern.
Is a windmill a double check?
A windmill uses discovered checks, but each individual discovered check may or may not be a double check. In a REGULAR-DISCOVERED-CHECK windmill (the more common variant), the moving front piece does NOT check the enemy king from its new square — only the revealed piece behind checks. In a DOUBLE-CHECK windmill (rarer but more devastating), both pieces fire check simultaneously each rotation — the moved bishop or knight AND the revealed rook or queen. Double-check windmills are impossible to block or interpose against, so they harvest material without any defensive interference. Torre vs Lasker 1925 is a regular-discovered-check windmill; Alekhine vs Freeman 1924 has one rotation with a double check. See our /blog/what-is-a-double-check hub for the atomic-bomb mechanism.
What is the German name for windmill?
The German name is 'Mühle' (pronounced MYOO-luh), which is also the German word for a windmill. In German-language chess writing before World War II, 'Mühle' was the standard term and the English writers borrowed 'the mill' as a shorter form — the American Chess Bulletin used 'the mill' interchangeably with 'the seesaw' in the 1920s. After Torre vs Lasker Moscow 1925 was widely published, the term 'windmill' stabilised in English. Russian chess writing uses 'мельница' (mel'nitsa — literally 'mill'). Every major chess-language canon has a single word for this specific pattern, which reflects how universally recognisable it is.
Do chess engines find windmills?
Yes — modern engines find windmills at depth 3–5 because the discovered-check battery and the two-square king corridor are trivial pattern-recognition heuristics in every top engine (Stockfish's 'trapped king' bonus, Leela's positional evaluation network, Komodo's piece-coordination score). Engines specifically look for repeating-check cycles where the moved piece captures material each iteration, so any human-missable windmill will appear as a +∞ evaluation spike in the engine's post-game review at chess.rodeo. If your opponent misses a windmill you played, the analysis will flag the missed rotation with a red arrow; if you missed one against your opponent, the same analysis will show the exact capture sequence you should have played.
Where can I practise windmills for free?
Start with the two atomic-mechanism guides at /blog/what-is-a-discovered-attack and /blog/what-is-a-double-check for the underlying discovered-check-battery pattern that every windmill uses. Then read the /blog/what-is-a-battery-in-chess hub for the static setup that windmills spin. Then step through Torre vs Lasker Moscow 1925 (five rotations), Adams vs Torre New Orleans 1920 (the earlier proto-windmill), Alekhine vs Bogoljubov Hastings 1922 (three rotations on the g-file), and Fischer vs Benko US Championship 1963/64 (two rotations before Fischer switched to mate) in our free PGN Viewer — every game is a textbook windmill from setup to firing. Then play live rated games at chess.rodeo where Stockfish flags every 'windmill available' opportunity in the post-game review — every game with a discovered-check battery aimed at a cornered king gets a note if the seesaw rotation was missed. No account, no signup, no paywall on any of the three tools.
Play any game — let Stockfish flag every windmill you missed free
Import your games into chess.rodeo, hit Analyze, and every game with a discovered-check battery aimed at a cornered king gets a note if the seesaw rotation was missed. Free, no account, no paywall.