Harrwitz Attack

The Harrwitz Attack places White's queen's bishop on f4 rather than g5. On g5 the bishop invites simplifying ideas such as ...Ne4, familiar from the Lasker Defense, and can be traded for the f6-knight or chased with ...h6 to give Black the bishop pair. From f4 it avoids these exchanges, eyes c7 and the long diagonal, and still leaves e3 free so the light-squared bishop can come out. After the direct 4. Bf4, Black's most frequent replies are 4...Bb4, 4...Bd6 and 4...Be7, and the engine considers the position level. The line more often arises via 1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. Nf3 Be7 5. Bf4.

The main line goes 5...O-O 6. e3 c5 7. dxc5 Bxc5. Here Black strikes at the center at once and accepts a possible isolated d-pawn after ...dxc4, in exchange for active pieces. The quieter alternatives are named by Black's sixth move: 6...c6, the Orthodox Defense; 6...b6, the Fianchetto Defense; and 6...Nbd7, the Two Knights Defense. The variation has elite pedigree. Fischer played it in game 14 of the 1972 match with Spassky, and Leko used it to defeat Kramnik during their 2004 world championship match.