Petrov's Defense: Classical Attack, Mason Variation
Play any move on the board to explore from there, or step through the line with ‹ › and the arrow keys.
Statistics from Lichess
103,108 games: White 51.7% / Draw 7.3% / Black 41.0%
| Next move | Games | White / Draw / BlackW / D / B |
|---|---|---|
| 42,53943K | ||
| 39,89740K | ||
| 6,0886,088 | ||
| 5,9645,964 | ||
| 2,9432,943 | ||
| 2,1012,101 | ||
| 1,7591,759 | ||
| 680680 |
Rated Lichess games between players rated 1600 to 2500, from the Lichess opening explorer, updated Oct 13, 2026
Engine evaluation
+0.33 White is slightly better
Best play: 8. c4 Nf6 9. Nc3 Nc6 10. h3 Nb4 11. c5 Nxd3 12. Qxd3 Re8
Stockfish 19, depth 30, after the line's last move. Scores are in pawns, from White's side.
Overview
Petrov's Defense: Classical Attack, Mason Variation (ECO C42, Open Games) is a variation of Petrov's Defense: Classical Attack, reached after 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4 d5 6. Bd3 Be7 7. O-O O-O (7 moves).
In 103,108 rated Lichess games between players rated 1600 to 2500, White won 51.7%, Black 41.0% and 7.3% were drawn. White's most played move here is 8. c4, in 41% of those games.
Written from the Lichess opening list and explorer. Know this line well? Write about it.
Write a description or report a mistake
How to play against Petrov's Defense: Classical Attack, Mason Variation
The most played answer, 8. c4, also scores best for White: 57.4%, with White winning 53.8% and Black 39.0% of 43K games. Of the main answers, 8. Nbd2 scores lowest: 52.1%. Stockfish's first choice is also 8. c4.
Main answers: those played in at least 5% of these games. Score: White's wins plus half the draws, in rated Lichess games between players rated 1600 to 2500. How to play against other popular openings
Cite this page
Caissa Codex. “Petrov's Defense: Classical Attack, Mason Variation (C42)”. Lichess data as of 13 Oct 2026. https://chesscodex.org/openings/petrovs-defense-classical-attack-mason-variation