The swallowtail mate
A queen face to face with the king, and the two squares it would have backed away to filled by its own pieces.
- 16 positions in the course match this pattern
- Lichess rating 1132–2226
- Section: Checkmate Patterns
- Every line verified by the app’s rules engine
The pattern
The queen stands directly next to the king, on its rank or its file, and gives check. As always with a queen at touching distance, it has to be defended by something.
The two squares diagonally behind the king are occupied by pieces of its own -- classically the two rooks, which is what gives the arrangement its forked, swallow's-tail outline. The queen covers the remaining three squares from where it stands.
The mirror of this is the dovetail mate, where the blockers are directly beside the king and the queen is on the diagonal. Both patterns are one supported queen and two of the defender's own pieces; only the angle changes, and the angle is the whole thing to learn.
What is always true
Each line below was tested against all 16 positions in this course that show the pattern, using the same rules engine the trainer runs on. The build stops if any of them is ever false, so the count beside each one is the real count.
- The checking piece is a queen 16/16
- The queen stands directly beside the king, on its rank or file 16/16
- At least two squares beside the king are blocked by its own pieces 16/16
- Every one of those blocked squares is diagonal to the king 16/16
How to spot it
- A king in the open with two of its own pieces trailing behind it on the diagonals. Kings walking up the board in a queen endgame do this constantly.
- A queen with a defender that can step to the square in front of the king. The defender can be a pawn, a knight, or a king of your own.
- The blockers before the check. If either diagonal square is empty the check is not mate, and if you have already given the queen away for it, that is the whole game.
- Your own king in a queen endgame. This is the pattern that turns a perpetual into a loss.
4 positions to solve
Real games, easiest first. The amber squares are the move your opponent has just played, not the answer. Work it out before you open the solution; the second diagram inside each answer is the finished mate with the trapped king outlined.
Position 1
White to move. Force the mate.
Show the answer
22...Rf8 23.Qh5+ Kf6 24.Qf5#
The black king on f6 is in check from the queen on f5, which the pawn on g4 defends. It has eight squares to try and none of them work: e5, e6, f7, g5 and g6 are covered by the queen on f5; e7 and g7 are blocked by its own pieces; the queen on f5 cannot be taken, because the pawn on g4 defends it.
The position comes from an endgame of a real game, rated 1132 in the Lichess pool and scored there as mate in two. The amber squares on the first diagram are the move your opponent had just played.
Position 2
White to move. Force the mate.
Show the answer
18...Ke7 19.Qd7#
The black king on e7 is in check from the queen on d7, which the knight on c5 defends. It has eight squares to try and none of them work: d8, e6, e8 and f7 are covered by the queen on d7; d6, f6 and f8 are blocked by its own pieces; the queen on d7 cannot be taken, because the knight on c5 defends it.
The position comes from the middlegame of a real game, rated 1423 in the Lichess pool and scored there as mate in one. The amber squares on the first diagram are the move your opponent had just played.
Position 3
White to move. Force the mate.
Show the answer
37...Kf8 38.Qg7+ Ke7 39.Qxf7#
The black king on e7 is in check from the queen on f7, which the bishop on d5 defends. It has eight squares to try and none of them work: d7, e6, e8, f6 and f8 are covered by the queen on f7; d6 and d8 are blocked by its own pieces; the queen on f7 cannot be taken, because the bishop on d5 defends it.
The position comes from an endgame of a real game, rated 1905 in the Lichess pool and scored there as mate in two. The amber squares on the first diagram are the move your opponent had just played.
Position 4
White to move. Force the mate.
Show the answer
19...exd4 20.Bd6+ Qxd6 21.Qh8+ Ke7 22.Qxe8#
The black king on e7 is in check from the queen on e8, which the bishop on g6 defends. It has eight squares to try and none of them work: d7, d8, e6, f7 and f8 are covered by the queen on e8; d6 and f6 are blocked by its own pieces; the queen on e8 cannot be taken, because the bishop on g6 defends it.
The position comes from the middlegame of a real game, rated 2226 in the Lichess pool and scored there as mate in three. The amber squares on the first diagram are the move your opponent had just played.
Where the name comes from
It has two names and both of them describe the picture rather than a person: swallow's tail for the forked outline the blocked squares make behind the king, and gueridon, the French word for a small pedestal table, for the same arrangement seen the other way up.
Easy to confuse with
These are the patterns Swallowtail Mate gets mistaken for. The difference is usually one piece or one square.
- Dovetail MateQueen diagonally adjacent, king boxed by its own
- Epaulette MateThe king's own pieces either side of it
- Kill Box MateRook adjacent, queen a knight's move away
Questions people ask
What is the swallowtail mate?
A checkmate in which a supported queen checks from directly beside the king while the two squares diagonally behind the king are blocked by its own pieces.
Is the swallowtail mate the same as the gueridon mate?
Yes. Both names describe the same arrangement of pieces.
How is it different from the epaulette mate?
In the epaulette mate the king's own pieces are directly either side of it and the checking piece can be a rook. In the swallowtail the blockers are diagonal and the checking piece has to be a queen, because it has to cover squares on both a rank and a diagonal at once.
All the named mates
One page each, or the whole set as a single motif in the course. The rest of the tactics library is at every motif in the course.
- Anastasia's MateKnight and rook, king on the edge file
- Arabian MateRook and knight against a cornered king
- Boden's MateTwo bishops on crossing diagonals
- Opera MateBack-rank rook with a bishop defending it
- Pillsbury's MateRook down the file, bishop on the long diagonal
- Morphy's MateBishop checks the corner, rook seals it
- Epaulette MateThe king's own pieces either side of it
- Dovetail MateQueen diagonally adjacent, king boxed by its own
- Hook MateRook, knight and pawn in a chain
- Kill Box MateRook adjacent, queen a knight's move away
- Corner MateKnight gives the check, a rook covers the rest
- Double Bishop MateTwo bishops on neighbouring diagonals