Fool's Mate

Fool's mate is the fastest checkmate in chess, and it punishes a player who weakens the king's diagonal with f3 and g4. The queen moves to h4 and gives check on the diagonal, and the pawns on f3 and g4 block the king's escape.

The finished shape

This is the finished shape. Fool's mate is the fastest checkmate in chess, and it punishes a player who weakens the king's diagonal with f3 and g4.

FEN: rnb1kbnr/pppp1ppp/8/4p3/6Pq/5P2/PPPPP2P/RNBQKBNR w KQkq - 1 2

a b c d e f g h
8 r n b . k b n r 8
7 p p p p . p p p 7
6 . . . . . . . . 6
5 . . . . p . . . 5
4 . . . . . . P q 4
3 . . . . . P . . 3
2 P P P P P . . P 2
1 R N B Q K B N R 1
  a b c d e f g h

The worked example

Here is the mating move. The queen moves to h4 and gives check on the diagonal, and the pawns on f3 and g4 block the king's escape.

FEN: rnbqkbnr/pppp1ppp/8/4p3/6P1/5P2/PPPPP2P/RNBQKBNR b KQkq - 0 1

a b c d e f g h
8 r n b q k b n r 8
7 p p p p . p p p 7
6 . . . . . . . . 6
5 . . . . p . . . 5
4 . . . . . . P . 4
3 . . . . . P . . 3
2 P P P P P . . P 2
1 R N B Q K B N R 1
  a b c d e f g h

How to prevent it

The defender plays Nc3 instead, and the trap no longer works.

FEN: rnbqkbnr/pppp1ppp/8/4p3/8/5P2/PPPPP1PP/RNBQKBNR w KQkq - 0 2

a b c d e f g h
8 r n b q k b n r 8
7 p p p p . p p p 7
6 . . . . . . . . 6
5 . . . . p . . . 5
4 . . . . . . . . 4
3 . . . . . P . . 3
2 P P P P P . P P 2
1 R N B Q K B N R 1
  a b c d e f g h

Key points

The queen moves to h4 and gives check on the diagonal, and the pawns on f3 and g4 block the king's escape.
The worked example ends with Qh4.
To prevent it, do not weaken the king's diagonal with early pawn moves in front of the king.
Black or White plays Nc3 in the prevention position, and the trap 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.

Ne7 Nh6 Nf6 Qh4#