Swallow's-tail mate
Also known as Guéridon mate, Gueridon mate
The queen mates directly in front of an enemy king whose two escape squares behind it are blocked by its own pieces. A friendly piece guards the queen so the king cannot capture it, and the king's own rooks (or pieces) form the "wings" that give the pattern its swallow's-tail shape.
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How it works
The black king on e8 has five neighbouring squares. Its own rooks sit on d8 and f8, so those flights are blocked. The white queen lands on e7, right in front of the king: from there it touches e8 and also covers d7 and f7, the remaining escape squares. The king would love to capture the queen, but the bishop on b4 guards e7 along the b4–e7 diagonal, so Kxe7 is illegal. With every square covered or blocked and nothing able to interpose or take the queen, it is mate.
How to spot it
Look for an enemy king boxed in by its own pieces on the two squares diagonally behind it (relative to your attack), leaving a clear square straight in front. If you can plant a defended queen on that front square, the swallow's tail snaps shut. It often appears in the endgame when a king is herded to the edge, or in the middlegame when castled rooks and a knight or pawn fence the king in. Always check that your queen will be protected – the supporting piece is what makes it mate rather than a free queen.
Key ideas
- The king's own pieces block the two squares diagonally behind it – the 'tail'.
- The queen mates from directly in front, covering the front and side escapes.
- A supporting piece must guard the queen so the king cannot capture it.
- Closely related to the Guéridon mate, where rook flanks form a pedestal-table shape.
- Drive the king to a square where its own army hems it in, then deliver the protected queen.
Famous example
A classic teaching position: a king with rooks on either flank, mated by a bishop-supported queen on the seventh rank. The shape resembles a swallow's forked tail, which gives the pattern its name; the French term Guéridon likens the same shape to a small three-legged pedestal table.