Zwischenzug
A zwischenzug, German for in-between move, interrupts a sequence both sides expect: instead of recapturing or answering a threat at once, a player slips in a check or bigger threat first.
Also called: in-between move, intermezzo
Zwischenzug is the German word for an in-between move. Most players think in a simple rhythm: you capture, I recapture. A zwischenzug breaks that rhythm. Instead of making the move everyone expects, you insert another move first, one that forces a reply, and only then carry on with your original plan.
The in-between move is almost always forcing. A check is the most common, because the opponent has to deal with it at once. A threat to a bigger piece, or a capture that creates a second threat, works too. The idea is that the extra move changes the position before the expected exchange is finished, so the exchange you were about to play now ends better for you, or the opponent's own plan no longer works.
To spot one, stop before every automatic recapture and ask whether any check, capture or threat is available first. Then look at what that move would gain. Often it forks two pieces, drags the king to a bad square or wins a piece with tempo. To defend, do not assume your last move left the opponent with only one sensible reply. Before you capture or move a piece into danger, look for checks the other side could play in between.
In the diagram White is to move. Black's queen on f7 attacks the knight on f5, so the natural dxe5 would simply lose the knight to Qxf5. Instead White plays Nh6+, a check that must be answered. After Kg7 or Kf8, Nxf7 takes the queen and White collects the bishop next. After Kh8, Nxf7+ takes the queen with check and also attacks the bishop on e5.
Compare it with Double attack. A double attack is one move that creates two threats at once, whether they come from a single piece or from two, and whether they aim at pieces or at checkmate.
Compare it with Legal's mate. Legal's mate is an opening trap in which White lets Black capture the queen and then checkmates with a bishop and two knights, punishing a Black player who takes the offered piece.
A neighboring idea is Relative pin. A relative pin is a pin in which the piece behind the pinned piece is more valuable but is not the king, so the pinned piece may legally move but would lose that piece.
Knowing "Zwischenzug" helps most once you can spot it in a real game. A first lesson with George Li starts from your own games and finds the tactics you keep missing.
Related terms
A fork is a move that leaves one of your pieces threatening two enemy pieces together. Because the opponent gets only one turn to respond, something usually falls.
A double attack is one move that creates two threats at once, whether they come from a single piece or from two, and whether they aim at pieces or at checkmate.
A discovered check is a check from a piece that did not move: a bishop, rook or queen is unmasked when the piece in front of it leaves the line to the king.
A combination is a forcing sequence of moves, usually built from sacrifices and checks, in which every move leaves the opponent few or no choices and the sequence ends in a concrete gain such as mate or material.
Guides that go further
What to decide first, the questions to ask, what a first lesson should show and the red flags to avoid.
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