Petrov's Defense: Paulsen Attack: Plans and Traps

Key ideas for both sides

White

After 4...Nxe4 play Nc3 and recapture on c3 with the d-pawn to open the d-file.
Route the c4 knight to e3 and d5, where it presses c7 and supports an attack.
Against ...Qe7, defend with Be2 and O-O, then push d4 when the e-file pin is gone.
Keep the c4 knight centralized; it controls e5 and b6 and supports a later b4 push.

Black

Take on e4 with the knight. The pawn is free and Black's pieces develop smoothly.
After Nc3 trade on c3, then play ...Nc6, ...g6 and ...Bg7 to fight for d4 and d5.
Use ...Be6 to challenge the knight once it reaches e3 or d5.
...Qe7 pins the e4 pawn but costs time when the queen has to go back to d8.

Plans and pawn structure

In the main line, 4...Nxe4 5.Nc3 Nxc3 6.dxc3, White has doubled c-pawns and an open d-file. White plays Ne3, Nd5, Be2 and Qd2 or Bd3, often castling long. Black develops with ...Nc6, ...g6, ...Bg7 and ...O-O, then uses ...Be6 to remove the knight from d5. Material is equal and the position is level; White hopes for activity on the d-file, Black for a better structure later.

Where the engine's main line heads: White has doubled c-pawns. White's c-pawns are doubled, usually after ...Bxc3 bxc3. In return White keeps the bishop pair and a solid center.

What the engine plays from here

Stockfish 17.1 at depth 20 rates the position +0.04: level. Its three top choices for Black:

+0.04 4...Nxe4 5.Nc3 Nxc3 6.dxc3 Nc6 7.Ne3
+0.58 4...Qe7 5.Be2 Nxe4 6.O-O Qd8 7.d4
+0.86 4...Nc6 5.d3 d5 6.exd5 Nxd5 7.d4

Pawns, from White's side.

How it scores on lichess

269 rated lichess games reached this position; White scored 49.4%.

under 120048.2%

1200–159949.0%

1600–199945.1%

2000 and up62.9%

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

How to play against it

As Black, take with 4...Nxe4 and trade on c3 after Nc3. Fianchetto the dark bishop with ...g6 and ...Bg7, and challenge the d5 square with ...Be6 and ...c6. Avoid early queen moves that cost tempi.

Questions

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

The Petrov's Defense: Paulsen Attack starts 1.e4 e5 2.Nf3 Nf6 3.Nxe5 d6 4.Nc4. Its ECO code is C42.

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

Stockfish 17.1 rates the position +0.04 at depth 20, which is level. In 269 lichess games from our sample, White scored 49.4%. A rare but sound sideline for White players who want an unusual knight route, while Black gets level play by simple development.

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

White drops the knight back to c4 rather than f3. After 4...Nxe4 5.Nc3 Nxc3 6.dxc3, White plays Ne3 and Nd5 with an open d-file, while Black fianchettoes and challenges d5 with ...Be6.

What should Black play next?

The engine's first choice is Nxe4, with Qe7 and Nc6 close behind. 4...Nxe4 regains the pawn at once and keeps a level, simple position.

Updated October 2026. Sources and method.

Petrov's Defense: Paulsen Attack