Tuesday, February 5, 2013

Bishop and knight versus rook and pawn

Every beginner learns that a bishop or knight is worth three pawns, while a rook is worth five. It follows that a bishop and knight are worth six pawns, as is a rook and pawn, so exchanging bishop and knight for rook and pawn is an even exchange. In practice, however, it is rarely so simple.

Often a player has the opportunity to make such an exchange in the opening by giving up a bishop and knight for rook and pawn on the f7 or f2 square. This is rarely a good idea: the opponent's bishop and knight can get very active before the "extra" rook has a chance to get into play.

These themes are illustrated by the following game, where my minor pieces and queen whipped up a winning attack while my opponent's rook sat, unmoved, on a1. In the final position my opponent flagged while futilely searching for a defense against my dual threats of 24...Qxh2# and 24...Nxf2+ 25.Kg1 Qxg2#.

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