What is a bishop fork in chess?

A bishop fork is a type of fork in which a bishop moves to a square where it attacks two enemy pieces simultaneously along one or two different diagonals. Because the bishop is color-bound, both targets must sit on the same square color, making bishop forks comparatively easy to spot.

The white bishop controls two diagonals, attacking the black king and rook simultaneously.

What makes a bishop fork different from other forks?

A bishop fork works exclusively along diagonals. Unlike a rook fork, which operates along ranks (horizontal rows) and files (vertical columns), the bishop fork requires both targets to sit on the same color squares as your bishop. This color constraint makes bishop forks harder to pull off... but on the other hand, its diagonal movements can be tricky to spot!

Because bishops move any number of squares, a bishop fork can stretch across the entire board. Your bishop does not need to be close to its targets, it only needs a square where diagonals converge on two enemy pieces. That intersection square is everything, but only if your bishop is safe there!

The white bishop forks the black king and knight by attacking along a single diagonal. Engine-verified position, Elo 518.

How do you defend against a bishop fork?

The simplest defense against a bishop fork is prevention. Be careful placing two valuable pieces on same-colored squares where an enemy bishop can reach both.

If the fork has already arrived, options are limited... but not zero. Don't forget to check if you can simply take the bishop; your opponent could have missed it! But if they didn't do you that favor (and you're not in check), you might still be able to defend one piece by moving the other, or find a counterattack: one piece moving out of the fork with check can buy you time to save the other.

A black bishop forks the white rooks, but one moves away with check. The second rook can capture a free pawn.

See it in action

Example 1: Bishop forks king and rook

Fork and capture.

Solution: The white bishop moves two squares to take the pawn, forking the rook and king. The black bishop has to block the check. The white bishop captures the rook.

Example 2: Bishop forks queen and knight

Find the bishop fork.

Solution: The white bishop moves two squares diagonally, attacking the queen and knight. Black can only save one: the queen. The knight is lost.

Example 3: Bishop fork with check

Find the fork.

Solution: The black bishop swings to the center, checking the white king diagonally and attacking the knight. The king must move out of check, leaving the knight to be captured.

Frequently asked questions

Is a bishop fork stronger when it includes a check?

Not always. When the fork works, it works! Without check, your opponent has more options available, so try to anticipate possible defenses before moving. Don't rush!

Why are bishop forks less common than knight forks?

Due to the knight's L-shaped movement, forkable squares are often overlooked by newer players. Bishop forks are generally easier to spot in comparison, especially when moving quickly. But that doesn't mean you won't get plenty of them!