Bishop or knight? How to judge the minor pieces

Published 27 October 2026

Bishops and knights are both counted as about three pawns, and beginners are usually taught to treat them as equal. That is a good starting point and a poor finishing one. The two pieces move in completely different ways, and in a given position one of them can be clearly better than the other. Deciding which one you want, and steering the game towards positions that suit it, is one of the first real strategic skills in chess. This article explains the main factors. Diagrams were checked with a chess rules library, and the endgame result quoted near the end was confirmed with an endgame tablebase.

How the two pieces differ

A bishop is a long-range piece. From the centre of an empty board it controls thirteen squares, and it can cross the board in one move. Its weakness is that it can only ever use squares of one colour, so half the board is permanently out of its reach.

A knight is a short-range piece. It controls at most eight squares, and it needs several moves to get from one side of the board to the other. In return, it can reach every square on the board eventually, it jumps over other pieces, and it attacks squares of both colours, alternating with every move.

Almost every rule of thumb about bishops and knights follows from these two descriptions.

Open positions favour the bishop

When the centre pawns have been exchanged and the long diagonals are clear, the bishop's range counts. It can defend on one side of the board and attack on the other at the same time. If there are pawns on both wings, a knight struggles to cover both, because it takes three or four moves to switch sides.

An open position with pawns on both wings. The bishop on b3 can watch both sides of the board; the knight needs several moves to cross over. (White to move.)

In positions like this one the bishop is usually considered the better piece. It can attack the a7 pawn and the kingside pawns from a distance, while the knight must choose one side at a time.

Closed positions and outposts favour the knight

When pawns are locked in the centre, the diagonals are blocked and the bishop's range disappears. The knight, which jumps over obstacles, does not mind. It is particularly strong on an outpost: a square in or near the enemy half of the board that no enemy pawn can attack, ideally protected by one of your own pawns.

The knight on d5 sits on an outpost: no black pawn can ever attack it. The black bishop on e7 is hemmed in by its own pawns on d6 and e5. (White to move.)

Look at the two pieces. The white knight on d5 is protected by the e4 pawn and cannot be driven away, because Black has no c-pawn and the e-pawn has already passed that rank. From d5 it eyes e7, c7, b6 and f6. The black bishop on e7 stands on a dark square, and its own pawns on d6 and e5 are also on dark squares, so they block its diagonals.

Good bishops and bad bishops

That last observation is worth stating as a rule. A bishop is called bad when many of its own side's pawns stand on squares of its colour, especially fixed centre pawns. It is called good when its pawns are on the other colour, leaving its diagonals open. A bad bishop is still a piece and can still defend, but it is often passive.

The practical consequence goes both ways. If you have one bishop left, try to put your pawns on the opposite colour. If your opponent has a bad bishop, try to keep the pawns fixed and exchange your own good pieces until that bishop is the only thing left to defend with.

The bishop pair

Two bishops together cover squares of both colours, so their main weakness disappears. Many players and trainers regard the bishop pair as a small but lasting advantage in open positions, worth something like half a pawn. That is a rule of thumb rather than a law, but it explains why strong players sometimes give up a knight for a bishop early in the game even when nothing seems to be gained: they are acquiring the pair.

The endgame: when a bishop cannot win

In endgames, bishops are usually slightly better than knights when there are pawns on both wings, and knights do well when all the pawns are on one side. But one endgame shows that a bishop's colour can matter more than anything else: king, bishop and rook pawn against a lone king.

White has a bishop and an extra pawn, but the bishop on f1 runs on light squares and the queening square h8 is dark. (White to move.)

White is a whole bishop and a pawn ahead, and the tablebase still says this is a draw. The black king sits on h8, the queening square. A light-squared bishop can never attack h8 to drive it away, so White can only stalemate the king or let it stay there. Swap the bishop for one that runs on dark squares and the result changes:

The same position with a dark-squared bishop on c1, which can control h8. (White to move.)

This is called the "wrong-coloured bishop" ending, and it is worth knowing for both sides. If you are defending, trading down into it can save a lost game. If you are attacking, keep a different pawn or avoid exchanging into it.

A quick checklist

Are the centre pawns fixed or exchanged? Fixed favours knights, open favours bishops.
Are there pawns on both wings? That usually favours the bishop.
Does the knight have a secure outpost? A knight on a protected outpost can be as strong as a rook.
On which colour are your pawns? Put them on the opposite colour from your bishop.
In the endgame, does the bishop control the queening square of a rook pawn?

The next time you are about to exchange a bishop for a knight or the other way round, run through the list. You will not always find a clear answer, but you will make the exchange on purpose rather than by habit. For the related idea of improving your worst piece, see the strategy article.