Openings · C42–C43

Petrov's Defence

Answer the attack on e5 by attacking e4: symmetry as a defence, and the most solid reply to 1.e4 there is.

1.e4 e5 2.Nf3 Nf6played as Black

Play it through on the board below.

Practise the line

You play Black; the other side answers on its own. Nothing here is saved or graded.

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Your move 1 of 20/2
  1. 1.e4e5
  2. 2.Nf3Nf6

White is answering…

The idea

2…Nf6 ignores the threat and makes one of its own. If White takes on e5, Black does not take back at once — he plays …d6 first, kicks the knight, and only then collects the pawn on e4 with everything defended.

Its reputation is dry, and that is the point: Black is choosing a game with few weaknesses over a game with chances for both sides. The Petrov punishes an opponent who needs to win and has nothing to attack — and it has a surprising number of short, sharp traps for anyone who thinks symmetry means safety.

Common mistakes

Three that come up again and again below master level: named traps and the errors every coach corrects.

Taking back on e4 immediately

After 5.Nc6+
  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
The mistake
Answering 3.Nxe5 with 3…Nxe4 rather than 3…d6.
Why it costs
4.Qe2 pins the knight to nothing in particular — until 4…Nf6 5.Nc6+ arrives. It is a discovered check that also attacks the queen, and Black loses her for a knight on move five. This is the oldest trap in the opening and it still works.
Instead
3…d6 first, kicking the knight, and 4…Nxe4 after it moves. One move of patience is the whole difference.

The Stafford Gambit

After 5.d3
  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
The mistake
Meeting 3.Nxe5 with 3…Nc6, hoping for a trap.
Why it costs
The gambit is a pawn for a set of one-move threats, and every one of them has a quiet answer — 5.d3 and 6.Be2 defuse the whole thing. Against anyone who declines to cooperate, Black is simply a pawn down with doubled pawns.
Instead
3…d6. If you want an aggressive answer to 1.e4, play one that does not depend on your opponent being unfamiliar with it.

Grabbing the pawn on d4

After 5…d5
  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
The mistake
Taking on d4 instead of taking on e4.
Why it costs
4.e5 gains a tempo on the knight and White recovers the pawn with a space advantage and a comfortable game — precisely the sort of position the Petrov is played to avoid.
Instead
3…Nxe4, the main line. Black holds the extra piece for a moment and gives it back on his own terms after 4.Bd3 d5.

Essential for beginners

  • 1 in 31games end with Black giving checkmate by move 15. In all openings: 1 in 54.Quick wins
  • 1 in 23games end with Black getting checkmated by move 15. In all openings: 1 in 33.

From 12,627 Lichess games in this opening between players rated under 1200, blitz and slower, September 2026. How we counted.

What the engine says

After 1.e4 e5 2.Nf3 Nf6, these are White's six best moves according to Stockfish, with the bar showing White's chance of winning.

  1. Nxe5+0.4
  2. d4+0.3
  3. Nc3+0.1
  4. d3-0.0
  5. Be2-0.1
  6. g3-0.2

The engine's main line from Nxe5: Nxe5 d6 Nf3 Nxe4 d4 d5 Bd3 Bd6.

Stockfish 18, depth 24. Scores are in pawns from White's side. Another engine or depth will move individual numbers a little; the picture does not change. How we check.

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