Chess Openings Lab
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Italian Game: Two Knights Defense, Polerio Defense

The Polerio Defense is 4.Ng5 d5 5.exd5 Na5, where Black leaves the d5 pawn and kicks the c4 bishop with the knight. White keeps an extra pawn but loses time; Black wants quick development and pressure with ...h6 and ...e4 against the g5 knight.

Moves
1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Ng5 d5 5.exd5 Na5
ECO
C58
Engine
+0.06 · level (Stockfish 17.1, depth 20)
Played
5,678 games in our lichess sample
White scores
47.7%

Key ideas for both sides

White

  • Check with Bb5+, the engine's top move, so ...c6 costs Black a pawn structure decision.
  • After the trade on c6, retreat Bd3 and bring the knight back to f3 to cover e5 and e4.
  • The quieter d3 and Be2 lines let Black gain space with ...h6 and ...e4, so treat them with care.
  • Castle soon and keep the extra pawn only if it does not cost the king's safety.

Black

  • After Bb5+, block with ...c6 and recapture ...bxc6 to open the b-file and gain the center.
  • Hit the g5 knight with ...h6 and push ...e4 so White's knight has no comfortable square.
  • Against d3 or Be2, the ...h6 and ...e4 pushes drive the knight to d4 and give Black a lead in space.
  • Develop with ...Bd6 or ...Bc5 and castle short, then use the rooks on the half-open files.

Plans and pawn structure

This is the classic Two Knights gambit. White is a pawn up, but the a5 knight harasses the bishop and Black gains time with ...c6, ...h6 and ...e4. White's plan is Bb5+, Bd3 or Be2, the knight back to f3 and short castling, then d3 or d4 to free the queenside pieces. Black's plan is to keep White's pieces passive, use the b-file and e-file, and later regroup the a5 knight toward the center. In this sample White scored 47.7%, so Black's compensation is real in practice.

What the engine plays from here

Stockfish 17.1 at depth 20 rates the position +0.06: level. Its three top choices for White:

  1. +0.06 6.Bb5+ c6 7.dxc6 bxc6 8.Bd3 Nd5
  2. −0.34 6.d3 h6 7.Nf3 e4 8.Nd4 Bc5
  3. −0.60 6.Be2 h6 7.Nf3 e4 8.Nd4 Qxd5

Pawns, from White's side.

How it scores on lichess

5,678 rated lichess games reached this position; White scored 47.7%.

under 120046.7%
1200–159945.6%
1600–199949.7%
2000 and up48.7%

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

Where it goes next

How to play against it

As White, play Bb5+ and accept that you must return to d3 or e2 later. Do not leave the bishop on c4 to be taken. Get the knight out of g5 before ...h6 and ...e4 trap it, and castle quickly.

Questions

What are the moves of the Italian Game: Two Knights Defense, Polerio Defense?

The Italian Game: Two Knights Defense, Polerio Defense starts 1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Ng5 d5 5.exd5 Na5. Its ECO code is C58.

Is the Italian Game: Two Knights Defense, Polerio Defense good for Black?

Stockfish 17.1 rates the position +0.06 at depth 20, which is level. In 5,678 lichess games from our sample, White scored 47.7%. A sound gambit for Black players who like initiative, and White needs to know Bb5+ and how to untangle the minor pieces.

What is the main idea of the Italian Game: Two Knights Defense, Polerio Defense?

Black gives up a pawn to gain time against White's bishop and knight. With ...Na5, ...c6, ...h6 and ...e4, Black develops fast while White untangles.

What should White play next?

The engine's first choice is Bb5+, with d3 and Be2 close behind. Bb5+ gains a tempo before the bishop has to retreat, forcing Black to commit with ...c6.

Updated October 2026. Sources and method.