ECO C42 · Petrov's Defense

Petrov's Defense: Classical Attack, Mason-Showalter Variation

1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4 d5 6. Bd3 Nc6

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White to move. The arrow shows Stockfish’s best move.
Best move

7. O-O+0.49

White is slightly better. Stockfish 18, depth 18.

Analyze this position

In the Petrov's Defense: Classical Attack, Mason-Showalter Variation (C42), reached after 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4 d5 6. Bd3 Nc6, Stockfish 18 recommends 7. O-O for White. White is slightly better (+0.49).

Top engine moves

  1. +0.497. O-O Be7 8. Nbd2 Nd6 9. c3 Bf5 10. Bxf5 Nxf5 11. Qb3 a6
  2. +0.337. Nbd2 Nxd2 8. Bxd2 Bd6 9. O-O O-O 10. Ng5 h6 11. Qh5 f5
  3. +0.297. Nc3 Nxc3 8. bxc3 Bd6 9. O-O O-O 10. Ng5 g6 11. Bd2 Qf6

Frequently asked questions

What is the best move in the Petrov's Defense: Classical Attack, Mason-Showalter Variation?
After 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4 d5 6. Bd3 Nc6, Stockfish 18 at depth 18 recommends 7. O-O for White, continuing Be7 8. Nbd2 Nd6 9. c3 Bf5 10. Bxf5 Nxf5 11. Qb3 a6. White is slightly better (+0.49). The next best moves are 7. Nbd2 (+0.33) and 7. Nc3 (+0.29).
Is the Petrov's Defense: Classical Attack, Mason-Showalter Variation a good opening?
Stockfish rates the position at +0.49: white is slightly better. Evaluations this early in the game are small, so practical results depend far more on knowing the plans and typical structures than on the engine's number.
What is the ECO code of the Petrov's Defense: Classical Attack, Mason-Showalter Variation?
C42. ECO codes classify chess openings from A00 to E99; C is the volume for open games and the French Defense.

Opening names from the Lichess opening book (CC0). Pieces by Colin M.L. Burnett (GPLv2+).