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

An entry in the Encyclopedia of Chess Openings (ECO C42), reached after 12 half-moves: 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4 d5 6. Bd3 Nc6.

Black rook — Use ← → arrows or click moves to step through.

Black bishop — Use ← → arrows or click moves to step through.

End of this line

No further variations branch from this position in our database. To explore neighbouring ideas:

About this opening

Petrov's Defense: Classical Attack, Mason-Showalter Variation is an opening in the Encyclopedia of Chess Openings, classified under code C42. ECO group C (C00–C99) covers open games (1.e4 e5) and the French Defence, including the Ruy Lopez, Italian, Scotch and King's Gambit. This particular variation is reached after 12 half-moves from the starting position, with the move sequence 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4 d5 6. Bd3 Nc6.

It belongs to the Petrov's Defense family. Within that family this is a level-2 branch (the Classical Attack → Mason-Showalter Variation line). The immediate parent line is Petrov's Defense: Classical Attack, transitioned via 6…Nc6.

The opening sequence in prose form: 1.e4 e5, 2.Nf3 Nf6, 3.Nxe5 d6, 4.Nf3 Nxe4, 5.d4 d5, 6.Bd3 Nc6. From this position the encyclopaedia records no further canonical continuations — practical play branches into unnamed transpositions or returns to the parent line for alternative ideas.