Caissa Codex
C42

Petrov's Defense: Classical Attack, Krause Variation

Chess diagram: Petrov's Defense: Classical Attack, Krause Variation after 10. c4

Type a move and press Enter: e4, Nf3, O-O, or from and to squares like g1f3 (e7e8q to promote). The board is also played with the mouse.

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Statistics from Lichess

95 games: White 56.8% / Draw 9.5% / Black 33.7%

The moves played next. Pick one to see it on the board.
Next moveGamesWhite / Draw / BlackW / D / B
3434
2525
1313
1010
77
Petrov's Defense: Classical Attack, Maróczy Variation 33
22
11

Rated Lichess games between players rated 1600 to 2500, from the Lichess opening explorer, updated Oct 31, 2026

Engine evaluation

−0.07 The position is about equal

Best play: 10... Bh4 11. Be3 f4 12. Bxe4 dxe4 13. Bxf4 Bxf3 14. gxf3 O-O 15. Rxe4

Stockfish 19, depth 30, after the line's last move. Scores are in pawns, from White's side.

Overview

Petrov's Defense: Classical Attack, Krause Variation (ECO C42, Open Games) is a variation of Petrov's Defense: Classical Attack, Mason-Showalter Variation, reached after 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4 d5 6. Bd3 Nc6 7. O-O Be7 8. Re1 Bg4 9. c3 f5 10. c4 (10 moves).

In 95 rated Lichess games between players rated 1600 to 2500, White won 56.8%, Black 33.7% and 9.5% were drawn. Black's most played move here is 10…O-O, in 36% of those games. That is too few games for the percentages to mean much.

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Other lines from the same position

Instead of 7. O-O Be7 8. Re1 Bg4 9. c3 f5 10. c4, the position after Petrov's Defense: Classical Attack, Mason-Showalter Variation also goes on to:

Transpositions

From here, a move transposes into another named line:

Cite this page

Caissa Codex. “Petrov's Defense: Classical Attack, Krause Variation (C42)”. Lichess data as of 31 Oct 2026. https://chesscodex.org/openings/petrovs-defense-classical-attack-krause-variation

https://chesscodex.org/openings/petrovs-defense-classical-attack-krause-variation