Piece value

What a piece is worth in play. Piece values can be absolute or relative: a knight, for example, is roughly worth a bishop or three pawns, two rooks are worth a queen, a queen three minor pieces, a rook a minor piece and two pawns. These are the absolute values.

Relative value

Depending on the concrete position that arises over the board, though, the absolute values break down and give way to relative ones. With a blocked pawn position the knight is stronger than the bishop, while in an open position, especially with play on both flanks, the bishop is far more mobile.

A minor piece is usually stronger than three pawns in the middlegame, whereas in the endgame the pawns may be preferable. The queen is stronger than two rooks in the opening and in the middle of the game when the position is closed and the rooks find it hard to work together; but once the rooks work together, especially in the endgame and with passed pawns on the board, the two rooks have the advantage over the queen.

The absolute values are broken very rarely, above all during tactical operations. Depending on how the pawns stand, the relative value of a piece can differ so far from its absolute value that the piece is called a "good piece" or a "bad piece".