The exchange (chess)

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The exchange in chess refers to a situation in which one player loses a minor piece (bishop or knight) but captures his opponent's rook. The side which wins the rook is said to have "won the exchange," while the other player has "lost the exchange." Subsequently, the side that has won the rook is "up the exchange", and the other player is "down the exchange". The opposing captures often happen on consecutive moves, although this is not strictly necessary. It is generally detrimental to lose the exchange, although occasionally one may find reason to purposely do so; the result is an exchange sacrifice (see below).

Note that this term differs from the more general "exchange" or "an exchange," which refers to the loss and subsequent gain of arbitrary pieces.

[edit] The exchange sacrifice

An exchange sacrifice occurs when one player gives up a rook for a minor piece. It is often used to destroy the enemy pawn structure (as in several variations of the Sicilian Defence where Black plays RxNc3), to establish a minor piece on a strong square (often threatening the enemy king), to improve one's own pawn structure (creating, for example, connected passed pawns), or to gain time for development. Tigran Petrosian, the world Champion from 1963-1969, was well known for his especially creative use of this device; in the game Reshevsky-Petrosian, Zurich 1953, he sacrificed the exchange on move 25, only for his opponent to sacrifice it in return on move 30 (the game ended in a draw); this game is perhaps the most famous and most frequently taught example of the exchange sacrifice.

[edit] Minor exchange

The minor exchange refers to the capture of the opponent's bishop for the player's knight (or, more recently, the stronger minor piece for the weaker). The term is rarely used. It can also refer to the capture of two of the opponent's minor pieces for the player's rook.

In most chess positions, a bishop is worth slightly more than a knight because of its longer range of movement. As a chess game progresses, pawns tend to get traded, removing support points from the knight and opening up lines for the bishop. This generally leads to the bishop's advantage increasing over time.

There are some occasions when a knight can be worth more than a bishop, so this exchange is not necessarily made at every opportunity to do so.