Dovetail Mate (Cozio's)

Dovetail mate, also called Cozio's mate, is a queen mate next to the king, where the queen's position makes a dovetail shape with the king's escape squares. The queen steps next to the king, and the white king protects the queen, so the king cannot take it.

The finished shape

This is the finished shape. Dovetail mate, also called Cozio's mate, is a queen mate next to the king, where the queen's position makes a dovetail shape with the king's escape squares.

FEN: 6bk/6Qp/5K2/8/8/8/8/8 b - - 1 1

a b c d e f g h
8 . . . . . . b k 8
7 . . . . . . Q p 7
6 . . . . . K . . 6
5 . . . . . . . . 5
4 . . . . . . . . 4
3 . . . . . . . . 3
2 . . . . . . . . 2
1 . . . . . . . . 1
  a b c d e f g h

The worked example

White plays the mating move here. The queen steps next to the king, and the white king protects the queen, so the king cannot take it.

FEN: 6bk/7p/5K2/8/8/8/8/6Q1 w - - 0 1

a b c d e f g h
8 . . . . . . b k 8
7 . . . . . . . p 7
6 . . . . . K . . 6
5 . . . . . . . . 5
4 . . . . . . . . 4
3 . . . . . . . . 3
2 . . . . . . . . 2
1 . . . . . . Q . 1
  a b c d e f g h

How to prevent it

Black plays h6 first. The pawn move opens an escape square, so the mate no longer works.

FEN: 6bk/7p/5K2/8/8/8/8/6Q1 b - - 0 1

a b c d e f g h
8 . . . . . . b k 8
7 . . . . . . . p 7
6 . . . . . K . . 6
5 . . . . . . . . 5
4 . . . . . . . . 4
3 . . . . . . . . 3
2 . . . . . . . . 2
1 . . . . . . Q . 1
  a b c d e f g h

Key points

The queen steps next to the king, and the white king protects the queen, so the king cannot take it.
The worked example ends with Qg7.
To prevent it, keep an escape square open and do not let the queen settle next to the king.
Black plays h6 first. The pawn move opens an escape square, so the mate no longer works.
Check every escape square before you play the mating move, because one open square breaks the mate.

Try it Yourself

Edit the code, then press Run.

Running is simulated · Rust Playground

Exercise

Find the checkmate in this position.

Qg7# Ke7 Kg5 Kf5