The Exchange (chess) - Value of The Exchange

Value of The Exchange

The value of the exchange (i.e. the difference between a rook and a minor piece) has been considered for decades. Siegbert Tarrasch put its value as 1½ pawns in the endgame, but not for the opening or the first part of the middlegame. That is widely accepted today, but Jacob Sarratt, Howard Staunton, and José Capablanca felt that the exchange was worth two pawns. Tigran Petrosian thought that one pawn was the right value. Wilhelm Steinitz said that a rook is slightly better than a knight and two pawns but slightly worse than a bishop and two pawns (Soltis 2004:110). Cecil Purdy said that the value depends on the total number of pawns on the board. The reason is that when there are many pawns, the rooks will have limited mobility because there will not be open files. The exchange is barely worth 1½ points when there are 14 or more pawns on the board. Only when there are ten or fewer pawns may the exchange be worth 2 points (Soltis 2004:134). Purdy gave the value as 1½ points in the opening and increasing to 2 points in the endgame. In the middlegame the value would be closer to 1½ than to 2 (Purdy 2003:146–52). Edmar Mednis gave the value as 1½ in the endgame (Mednis 1978:120), (Mednis 1987:107). Max Euwe put the value at 1½ in the middlegame and said that two pawns are more than sufficient compensation for the exchange (Euwe & Kramer 1994:38). Larry Kaufman's computer research puts the value as 1¾ pawns, but only 1¼ pawns if the player with the minor piece has the bishop pair (Soltis 2004:110). Hans Berliner puts the difference between a rook and knight as 1.9 pawns and the difference between a rook and a bishop as 1.77 pawns (Berliner 1999:14). In practice, one pawn may be sufficient compensation for the loss of the exchange, whereas two pawns almost always is (Soltis 2004:110).