Chess Openings Lab
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Petrov's Defense: Classical Attack

The Classical Attack is the Petrov main line 3.Nxe5 d6 4.Nf3 Nxe4 5.d4, where White builds a pawn center before chasing the knight on e4. White wants Bd3, short castling and c4 to undermine Black's outpost, while Black props up the e4 knight with ...d5 and develops calmly.

Moves
1.e4 e5 2.Nf3 Nf6 3.Nxe5 d6 4.Nf3 Nxe4 5.d4
ECO
C42
Engine
+0.38 · a slight edge for White (Stockfish 17.1, depth 20)
Played
1,227 games in our lichess sample
White scores
54.0%

Key ideas for both sides

White

  • Develop with Bd3 and O-O, as in every engine line, aiming the bishop at the knight on e4 and the h7 square.
  • Push c4 to attack d5, the pawn that supports the e4 knight, and open lines toward Black's center.
  • Put a rook on e1 to add pressure along the open e-file against the knight and the e7 bishop.
  • If ...Nb4 hits the d3 bishop, keep it with Be2 rather than allowing a trade of your best minor piece.

Black

  • Play 5...d5 to anchor the knight on e4; the symmetrical pawns give Black a solid, roughly level game.
  • Develop with ...Nc6 and ...Be7, then castle. The order is flexible but the knight on e4 needs ...d5 first.
  • Use ...Nb4 to chase the d3 bishop, and ...Bf5 or ...Bg4 to fight for e4 and pin the f3 knight.
  • Retreating with ...Nf6 is safe but passive; keep the knight on e4 while it is well supported.

Plans and pawn structure

The structure is a symmetrical d4 against d5 with an open e-file. White's main lever is c4: it hits d5, and if Black's support for the e4 knight collapses, Re1 and Nc3 win the outpost. Black answers with piece pressure: ...Nb4 against d3, ...Bf5 or ...Bg4, and ...c6 to hold d5. Both sides castle short. Exchanges on e4 tend to lead to quiet endgames with slightly freer play for White.

Where the engine's main line heads: Symmetrical center: d4 against d5, open e-file. A symmetrical center: d4 against d5 with an open e-file. Neither side has pawn weaknesses, so piece activity decides.

What the engine plays from here

Stockfish 17.1 at depth 20 rates the position +0.38: a slight edge for White. Its three top choices for Black:

  1. +0.38 5...d5 6.Bd3 Nc6 7.O-O Be7 8.c4
  2. +0.38 5...Be7 6.Bd3 d5 7.O-O Nc6 8.c4
  3. +0.41 5...Bf5 6.Bd3 d5 7.O-O Be7 8.Re1

Pawns, from White's side.

How it scores on lichess

1,227 rated lichess games reached this position; White scored 54.0%.

1200–159957.9%
1600–199953.9%
2000 and up52.7%

Light: White wins. Grey: draws. Dark: Black wins. About the sample.

Where it goes next

  • Classical Attack, Closed Variation5...Nf6 · rare
  • Classical Attack, Maróczy Variation5...d5 · rare

How to play against it

As Black, choose 5...d5 or 5...Be7 and keep the knight on e4 for now. Answer c4 calmly with ...Nb4 or ...c6. Do not release the tension in the center too early, since White's bishop then gets an open diagonal toward h7. Castle before starting any fight on the e-file.

Questions

What are the moves of the Petrov's Defense: Classical Attack?

The Petrov's Defense: Classical Attack starts 1.e4 e5 2.Nf3 Nf6 3.Nxe5 d6 4.Nf3 Nxe4 5.d4. Its ECO code is C42.

Is the Petrov's Defense: Classical Attack good for White?

Stockfish 17.1 rates the position +0.38 at depth 20, which is a slight edge for White. In 1,227 lichess games from our sample, White scored 54.0%. A solid choice for White players who like slow pressure, while Black needs patience and good piece placement more than memorized lines.

What is the main idea of the Petrov's Defense: Classical Attack?

White builds a center with d4, then plays Bd3, O-O and c4 to undermine the knight on e4. Black supports the knight with ...d5 and develops with ...Nc6, ...Be7 and ...Nb4, reaching a symmetrical center with level chances.

What should Black play next?

The engine's first choice is d5, with Be7 and Bf5 close behind. 5...d5 gives the knight on e4 a permanent pawn defender and mirrors White's center.

Updated October 2026. Sources and method.