Italian Game: Two Knights Defense

The Two Knights Defense (1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6) is a more aggressive answer to the Italian Game than 3...Bc5. Black develops the second knight and attacks e4 at once, accepting that f7 may come under fire.

Origins

The opening was first recorded by Giulio Cesare Polerio around 1580. It is also known as the Prussian Defense. In the 19th century Mikhail Chigorin showed Black's compensation in the main line with 5...Na5, and the defence has been played by many aggressive players, among them Chigorin, Paul Keres and the world champions Mikhail Tal and Boris Spassky. Siegbert Tarrasch famously called White's 4.Ng5 "a duffer's move" for breaking opening principles, yet it remains one of the main lines.

The idea

Black invites sharp play: after 4.Ng5 White attacks f7, and Black's only good defence is 4...d5, blocking the bishop. After 5.exd5 Black often gives up a pawn for quick development.

Main lines

• Knight Attack 4.Ng5 d5 5.exd5, and now:
  • 5...Na5, the Polerio Defense, also called the Chigorin Gambit, the main line: after 6.Bb5+ c6 7.dxc6 bxc6 Black is a pawn down but ahead in development;
  • 5...Nxd5?! allows the Fried Liver Attack 6.Nxf7;
  • 5...Nd4 (Fritz Variation) and 5...b5 (Ulvestad Variation).
• Traxler Counterattack 4.Ng5 Bc5: Black ignores the threat to f7 and counterattacks f2, which leads to wild complications.
• Modern Bishop's Opening 4.d3: a quiet positional line, often transposing to the Giuoco Pianissimo.
• Open Variation 4.d4: usually transposes to the Scotch Gambit, including the extensively analysed Max Lange Attack.

Strengths and weaknesses

Strengths

• Active piece play and early counterattack for Black.
• Many lines where White must know the theory or lose the initiative.
• Plenty of traps on both sides.

Weaknesses

• The main line costs Black a pawn, and Black must know how to use the lead in development.
• One careless move, such as 5...Nxd5 against a prepared opponent, can lose quickly.

Who should play it

The Two Knights suits active, tactically minded players who prefer counterplay to a slow Giuoco Piano. With White, it rewards players who know the Knight Attack theory; the quiet 4.d3 suits those who don't.

The numbers

On Lichess White does well at lower levels: 52.8% against 43.6% under 1400 and 51.6% against 44.8% between 1400 and 1800. Above that it is almost even: 48.9% against 46.7% at 1800–2199, and 47.1% against 46.3% from 2200 up. In master games over the board, White wins 31.4%, Black 24.6% and 44% are drawn.