Petrov's Defense: Classical Attack, Jaenisch Variation (C42)

The Classical Attack, Jaenisch Variation is a variation of the Petrov's Defense, catalogued as ECO C42. The line runs 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4 d5 6. Bd3 Nc6 7. O-O Be7 8. c4, reaching the position shown below after 15 half-moves.

Both sides have pawns in the centre (White on d4, Black on d5), and one pawn capture is available, so the structure has not settled yet. Development is level at two minor pieces each. It is Black to move after eight moves. White has castled while Black’s king is still uncommitted; the e-file file is fully open.

On the Petrov's Defense generally: A symmetrical defense known for its solidity. Black mirrors White's moves in the opening.

You can play through this variation move by move in your browser — Learn mode walks the line with an explanation at each step, and Drill mode replays it from memory so you find out whether you actually know it. No account is required.

Position characteristics

• Contested centre
• Open file

Related Petrov's Defense lines

• Classical Attack, Chigorin Variation
• Classical Attack, Chigorin Variation, Browne Attack
• Classical Attack, Chigorin Variation, Main Line
• Classical Attack, Closed Variation
• Classical Attack, Krause Variation
• Classical Attack, Marshall Trap
• Classical Attack, Marshall Variation
• Classical Attack, Marshall Variation, Chinese Gambit
• Classical Attack
• Classical Attack, Berger Variation

See all 30 Petrov's Defense variations →

Frequently asked questions

What are the moves of the Classical Attack, Jaenisch Variation?

The Classical Attack, Jaenisch Variation goes 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4 d5 6. Bd3 Nc6 7. O-O Be7 8. c4. It is a variation of the Petrov's Defense and is catalogued as ECO C42.

What is the ECO code for the Classical Attack, Jaenisch Variation?

The Classical Attack, Jaenisch Variation is ECO C42. ECO codes group openings by their move order, so nearby codes cover closely related lines of the Petrov's Defense.

Is the Classical Attack, Jaenisch Variation good for White?

Stockfish evaluates the position after 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4 d5 6. Bd3 Nc6 7. O-O Be7 8. c4 at +0.44 at depth 18, which is a slight pull for White, within normal opening margins. Engine evaluation is only a starting point — at club level the practical value of a line is mostly about whether you know its plans better than your opponent does.

What kind of position does the Classical Attack, Jaenisch Variation lead to?

Both sides have pawns in the centre (White on d4, Black on d5), and one pawn capture is available, so the structure has not settled yet. Development is level at two minor pieces each. It is Black to move. White has castled while Black’s king is still uncommitted; the e-file file is fully open.