Classical Attack

The Classical Attack, 5. d4, is White's most popular fifth move after 4...Nxe4 and the backbone of Petrov theory. The pawn claims the center and opens the way for Bd3. White then uses c4 and Re1 to undermine both the knight on e4 and the pawn on d5. Black nearly always replies 5...d5, propping up the knight. The alternative 5...Be7 often transposes. The retreat 5...Nf6, the Closed Variation, gives up the outpost for a solid but passive game.

After 5...d5 6. Bd3, Black chooses among three piece setups. The Mason-Showalter Variation, 6...Nc6, leads after 7. O-O Be7 8. c4 to the Jaenisch Variation, which has been popular for more than a century. There 8...Nb4 9. Be2 was popularized by Karpov, and Kramnik won twice with White against Leko in this line at the 2004 world championship match. The Marshall Variation, 6...Bd6, mirrors White's bishop and becomes the Staunton Variation after 7. O-O O-O 8. c4 c6. The quieter 6...Be7 7. O-O O-O is the Mason Variation. Engines give White only a slight edge, and the largely symmetrical structures help explain the opening's reputation for frequent draws.