Openings · C55–C59

Two Knights Defence

Counterattack rather than defend: 3…Nf6 hits e4 and dares White into 4.Ng5, the sharpest position in club chess.

1.e4 e5 2.Nf3 Nc6 3.Bc4 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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a
Your move 1 of 30/3
  1. 1.e4e5
  2. 2.Nf3Nc6
  3. 3.Bc4Nf6

White is answering…

The idea

Where the Giuoco Piano's …Bc5 develops quietly, …Nf6 asks a question. The critical answer is 4.Ng5, when Black must give up a pawn — 4…d5 5.exd5 Na5 — for a lead in development and lasting pressure. Nobody plays this opening for a quiet life.

It is the classical gambit test: material against time. Black is a pawn down for twenty moves in most lines and does not mind, because White's pieces are on bad squares and his king is still in the middle.

Common mistakes

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

The Fried Liver

After 7.Qf3+
  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
  6. 6.
  7. 7.
The mistake
Recapturing on d5 with the knight.
Why it costs
6.Nxf7 drags the king to f7 and 7.Qf3+ brings the queen with check. Black is not lost by force, but he is defending a king in the open for the rest of the game with no chance to castle, against an opponent who has known this line since he was ten.
Instead
5…Na5, hitting the bishop and giving the pawn back later. It looks like a rim move and it is the main line for good reason.

The Traxler, played as a surprise

After 5…Bxf2+
  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
The mistake
Meeting 4.Ng5 with the Traxler because it looks exciting, without having studied it.
Why it costs
It is a genuine piece sacrifice, and the difference between winning and losing runs eight or ten forcing moves deep from move five. 5.Bxf7+ — the quiet answer — is even more awkward for an unprepared Black than 5.Nxf7.
Instead
4…d5, the main line, unless you have the Traxler written down. This is the one opening where playing from general principles does not work.

Chasing the pawn back

After 8…Qd4
  1. 1.
  2. 2.
  3. 3.
  4. 4.
  5. 5.
  6. 6.
  7. 7.
  8. 8.
The mistake
Going after material once the compensation is in place.
Why it costs
8…Qd4 wins a pawn and loses the initiative: 9.Nf3 hits the queen and White gets to develop with tempo — the exact commodity Black paid a pawn for. The gambit is only worth it while White is the one making awkward moves.
Instead
8…h6 and 9…e4, driving the knight back and opening lines for the two bishops. Take the pawn back when it costs nothing, and not before.

Essential for beginners

  • 1 in 35games end with Black giving checkmate by move 15. In all openings: 1 in 54.Quick wins
  • 1 in 19games end with Black getting checkmated by move 15. In all openings: 1 in 33.Trap danger

From 10,360 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 Nc6 3.Bc4 Nf6, these are White's six best moves according to Stockfish, with the bar showing White's chance of winning.

  1. d3+0.3
  2. Ng5+0.2
  3. d4+0.1
  4. Qe2-0.1
  5. Nc3-0.2
  6. O-O-0.3

The engine's main line from d3: d3 Bc5 c3 d6 O-O a6 a4 Ba7.

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.

Where it fits

The Two Knights Defence is a variation of the Italian Game, whose page covers the ideas this one takes for granted.

Analyse a game you played in itAll openings