Petrov's Defense
Petrov's Defense arises after 1.e4 e5 2.Nf3 Nf6, where Black ignores the attack on e5 and counterattacks e4 instead. White tries to use the first move for a small, lasting edge in open positions, while Black aims for a symmetrical game with few weaknesses.
- Moves
- 1.e4 e5 2.Nf3 Nf6
- ECO
- C42
- Engine
- +0.37 · a slight edge for White (Stockfish 17.1, depth 20)
- Played
- 59,737 games in our lichess sample
- White scores
- 52.5%
Key ideas for both sides
White
- Take on e5 with Nxe5, the engine's first choice, then retreat with Nf3 after ...d6 and play d4 and Bd3.
- Play d4 at once in the Modern Attack, opening the center while Black's knight is still on f6.
- Choose Nc3 for a quieter Three Knights game that avoids most Petrov theory.
- In the Cozio Attack, Qe2 pins the e4 knight and heads for an early queen trade with a tiny edge.
Black
- After Nxe5, play ...d6 first and only then take on e4; the order is the whole point.
- Build a strong knight on e4 with ...d5, ...Be7 and ...O-O, keeping the center symmetrical.
- Against d4 lines, recapture on e4 and play ...d5 with quick development and easy equality.
- Use the Stafford Gambit, ...Nc6, only as a surprise: the engine shows a clear edge for White.
Plans and pawn structure
In the main line with Nxe5, ...d6, Nf3 and ...Nxe4, the center is symmetrical and the e-file is open. White plays d4, Bd3, O-O, c4 and Re1 to challenge the e4 knight and press on the open file. Black supports the knight with ...d5, ...Be7, ...Nc6 and ...Bg4 or ...Bf5, and trades pieces to reduce White's initiative. In the Three Knights and Italian lines, the game becomes a normal open game with fewer forcing lines.
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 Petrov's Defense is about
After 1.e4 e5 2.Nf3 Nf6 Black copies White's knight move and attacks e4. The idea is simple: instead of defending e5, Black counterattacks, and if White takes on e5, Black takes on e4. The positions that follow are often symmetrical, with an open e-file and few pawn weaknesses.
From this position White scored 52.5% across 59737 games. The engine's first choice is 3.Nxe5, and its main line runs 3...d6 4.Nf3 Nxe4 5.d4 d5 6.Bd3 Be7. The d4 lines and the quiet 3.Nc3 also keep a small edge or level play. The opening is known as a drawish, safe choice, but there are traps for both sides.
The key thing for a club player is move order. Black must not copy White blindly after 3.Nxe5, and White must not rush the knight back without a plan.
The main variations
The Three Knights Game, 3.Nc3, is the most played line in the packet. White defends e4 with a developing move and the game often becomes a Four Knights after ...Nc6. It avoids the sharp Petrov main lines.
The Italian Variation, 3.Bc4, invites ...Nxe4. The engine prefers Black there, so White must know the follow-up, often Nc3 with gambit play.
The Modern Attack, 3.d4, opens the center at once. After 3...Nxe4 4.dxe5 d5 Black gets a well-placed knight and quick development.
The Classical Attack, 5.d4, is the main line after 3.Nxe5 d6 4.Nf3 Nxe4. White plays Bd3, O-O, c4 and Re1 to challenge the e4 knight. The Cozio Attack, 5.Qe2, pins the knight and usually leads to a queen trade, and the Nimzowitsch Attack, 5.Nc3, trades knights at once.
Two lines are dangerous for the unprepared. The Stafford Gambit, 3.Nxe5 Nc6, gives a pawn for traps; White scored only 48.3% in practice even though the engine shows a clear edge for White. The Damiano Variation, 3.Nxe5 Nxe4, copies White and loses time; White scored 59.6%.
Typical plans for White
In the 5.d4 line White wants to undermine the e4 knight. The usual setup is d4, Bd3, O-O, then c4 and Re1. The c4 push attacks d5, which supports the knight. If the knight has to retreat, White is ahead in development and controls the center.
- Put a rook on e1 early. The open e-file is the main highway in this opening.
- Use Nc3 to trade the e4 knight when Black has spent time supporting it.
- In the Cozio Attack, Qe2 forces a queen trade with ...Qe7. White plays for a tiny edge in a calm endgame.
- In the Three Knights, Bb5 or d4 gives normal open-game play with no special risk.
White should accept that the edge is small. The goal is a slightly better position that Black must defend for a long time.
Typical plans for Black
Black's plan is to keep the knight on e4 as long as it helps, then trade it when needed. The standard setup is ...d5, ...Be7, ...Nc6, ...O-O and ...Bg4 or ...Bf5. Black copies White where it is safe and looks for equal trades.
- After 3.Nxe5, play ...d6 first. Taking on e4 at once allows Qe2 tricks and the Damiano lines.
- Against 3.d4, take on e4, then play ...d5 and develop. In the engine line, ...Nc5 and ...Bg4 give good piece play.
- Against the Cozio Attack, a queen trade with ...Qe7 is fine for Black. Develop the bishop to e7 or f5 and castle.
Mistakes club players make
- Black copying White with 3...Nxe4. After 3.Nxe5 Nxe4 4.Qe2, Black is in trouble. The Petrov queen trap shows the point: after 4...Nf6 5.Nc6+ the discovered check wins the queen.
- White falling for the Stafford traps. In the Stafford Gambit Bg5 trap, White grabs the queen on d8 with the bishop and gets mated after ...Bxf2+ and ...Bg4. Develop quietly with d3 and Be2 instead.
- White retreating the knight without a plan. After ...d6 the knight must go back to f3, but White needs d4 and Bd3 to make the extra tempo count.
- Black trading too much too early. Symmetry is not the same as safety. A passive Black position can still be ground down.
- 3.Bc4 without preparation. Black takes on e4 and the engine prefers Black.
Who should play it
Petrov's Defense suits Black players who want a low-risk reply to 1.e4 e5 2.Nf3 and are happy with equal positions they understand. It needs knowledge of a few key move orders, but the plans are simple.
For White, 3.Nxe5 is the critical test and the engine's choice. Players who dislike the symmetrical main lines can choose 3.Nc3 and reach a Three Knights or Four Knights game instead.
What the engine plays from here
Stockfish 17.1 at depth 20 rates the position +0.37: a slight edge for White. Its three top choices for White:
- +0.37 3.Nxe5 d6 4.Nf3 Nxe4 5.d4 d5
- +0.27 3.d4 Nxe4 4.dxe5 d5 5.Nbd2 Nc5
- +0.11 3.Nc3 Nc6 4.Bb5 Nd4 5.Nxd4 exd4
Pawns, from White's side.
How it scores on lichess
59,737 rated lichess games reached this position; White scored 52.5%.
Light: White wins. Grey: draws. Dark: Black wins. About the sample.
Traps and pitfalls
Petrov Defense queen trap (White sets it)
Black copies White with 3...Nxe4 in the Petrov, and 4.Qe2 puts the queen on the e-file. When the attacked knight retreats with 4...Nf6, 5.Nc6+ is a discovered check that also attacks the black queen.
Stafford Gambit Bg5 trap (Black sets it)
In the Stafford Gambit, White pins the f6 knight with 6.Bg5. Black ignores the pin with 6...Nxe4, and if White takes the queen with 7.Bxd8, the two black bishops and a knight mate the king on e2.
Variations of the Petrov's Defense
- Three Knights Game3.Nc3 · 15,724 games
- Italian Variation3.Bc4 · 13,616 games
- Stafford Gambit3.Nxe5 · 6,294 games
- Modern Attack3.d4 · 4,501 games
- Modern Attack, Trifunovic Variation3.d4 · rare
- Classical Attack, Maróczy Variation3.Nxe5 · rare
- Moody Gambit3.Qe2 · rare
- Boden-Kieseritzky Gambit, Lichtenhein Defense3.Bc4 · rare
- Spanish Variation, Symmetrical Variation, Tarrasch Variation3.Nc3 · rare
How to play against it
As White, take on e5 with Nxe5 and know the key move order: after ...d6, retreat with Nf3 before Black takes e4. If you want to avoid theory, Nc3 leads to a Three Knights game. Do not fall into the queen trap after ...Nxe4 Qe2: Black must not leave the knight to a discovered check.
Full guide: how to beat the Petrov's Defense
Other lines with this name
The lichess opening list also files these lines under the same name, though they reach a different position: 1.e4 e5 2.Nf3 Nf6 3.Nxe5; 1.e4 e5 2.Nf3 Nf6 3.Nxe5 d6; 1.e4 e5 2.Nf3 Nf6 3.Nxe5 d6 4.Nf3.
Questions
What are the moves of the Petrov's Defense?
The Petrov's Defense starts 1.e4 e5 2.Nf3 Nf6. Its ECO code is C42.
Is the Petrov's Defense good for Black?
Stockfish 17.1 rates the position +0.37 at depth 20, which is a slight edge for White. In 59,737 lichess games from our sample, White scored 52.5%. Ideal for patient Black players who want a reliable, low-risk defense and are happy to grind equal positions.
What is the main idea of the Petrov's Defense?
Black meets the attack on e5 with a counterattack on e4. If White takes on e5, Black plays ...d6 and then takes on e4, reaching a symmetrical position where White's edge is small.
What should White play next?
The engine's first choice is Nxe5, with d4 and Nc3 close behind. 3.Nxe5 wins the e5 pawn at once, and after 3...d6 4.Nf3 Nxe4 5.d4 d5 White keeps a slight edge in development.
Updated October 2026. Sources and method.