Inserting an unexpected, highly forcing move (usually a check, a mate threat, or a direct strike on a major piece) into a sequence where a standard, predictable move (like a recapture) is expected.
Why it matters
A zwischenzug is an in-between move: instead of making the recapture everyone expects, you insert something even more forcing first, and take afterwards.
It works because the expected move will still be there. A check does not go away, and neither does a hanging piece, so the free move is genuinely free.
See it on a board
The knight on d4 is not going anywhere, so the recapture can wait. The check cannot: take the pawn first, with the knight on g5 guarding the queen, and collect on d4 afterwards.
Checked: this line wins at least 4 pawns of material.
How to play it
- White plays Qxh7+!.
- This forcing check forces the Black King to move.
- Only after the King shifts out of danger does White calmly play Rxd4, completing the recapture under vastly superior strategic circumstances.
At each level
The same idea, said the way it is taught at each age.
Bishop · ages 5–7
Before you take back, ask whether you have a check first. If the capture will still be there afterwards, the check is free.
Rook · ages 6–9
Zwischenzug is why a calculated line can be wrong even when every move in it is right — one side inserted a check the other side never counted.
Queen · ages 8–11
Check every forcing move before the natural one, in your own lines and in your opponent's. Most of the time it changes nothing; when it changes something it usually decides the game.
What goes wrong
- Inserting an in-between move that is not forcing, so the opponent simply ignores it.
- Forgetting that the opponent has zwischenzugs too, in the middle of your own combination.
Questions people ask
- What does zwischenzug mean?
- It is German for "in-between move". Some players call it an intermezzo. Both mean the same thing: a forcing move inserted before the expected one.