Fork (chess)

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

The white knight forks Black's king and rook. Black's pawn forks the white rooks.

In chess, a fork is a tactic in which a piece attacks multiple enemy pieces simultaneously. The attacker usually aims to capture one of the forked pieces. The defender often cannot counter every threat. A fork is most effective when it is forcing, such as when the king is put in check. A fork is a type of double attack.

This article uses algebraic notation to describe chess moves.

Terminology

A fork is an example of a double attack. The type of fork is named after the type of forking piece. For example, a fork by a knight is a knight fork. The attacked pieces are forked.^[1] If the king is one of the attacked pieces, the term absolute fork is sometimes used, while a fork not involving the enemy king is a relative fork.^[2]

A fork of the king and queen, the highest material-gaining fork possible, is sometimes called a royal fork. A fork of the enemy king, queen, and one (or both) rooks is sometimes called a grand fork. A knight fork of the enemy king, queen, and possibly other pieces is sometimes called a family fork or family check.^[3]^[4]

Strategy

Any piece can deliver a fork. Forks are most often delivered by knights: a knight is not attacked by a piece it attacks except for an enemy knight, and it can be exchanged for a more valuable piece.^[5]^[6]

Compared to forks by other pieces, a queen fork requires more specific conditions to be helpful due to the queen's higher value. However, a queen fork can often lead to material or positional gain when the forked pieces are undefended, poorly coordinated, or when one piece is the king.^{[citation needed]}