Chess Openings Lab
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Italian Game: Two Knights Defense, Polerio Defense, Bishop Check Line

The Bishop Check Line is 6.Bb5+ in the Polerio Defense, gaining a tempo with check before the bishop retreats. Black usually blocks with ...c6, giving up a second pawn for rapid development, while White tries to hold the extra material.

Moves
1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Ng5 d5 5.exd5 Na5 6.Bb5+
ECO
C58
Engine
+0.03 · level (Stockfish 17.1, depth 20)
Played
3,296 games in our lichess sample
White scores
47.8%

Key ideas for both sides

White

  • After ...c6 dxc6 bxc6, retreat Bd3 so the bishop stays safe and covers e4.
  • Bring the g5 knight back to f3 and castle short, as in the top engine line.
  • Against ...Bd7, play Qe2 to pressure e5 and then Nf3 to win a central pawn.
  • If Black blocks with ...Nd7, jump Ne6 at once, using the pin on the d7 knight.

Black

  • Block with ...c6, the top engine move; after dxc6 bxc6 the b-file and center are Black's.
  • Follow with ...Nd5 and ...Bd6, putting both pieces on central squares quickly.
  • ...Bd7 is a calmer block, but White gets Qe2 and Nf3 against the e5 pawn.
  • Do not block with ...Nd7: Ne6 breaks open the king after ...fxe6 and dxe6.

Plans and pawn structure

After ...c6 and the trade on c6, Black has a pawn on c6, active knights and open lines, while White's bishop has gone to d3 and the knight back to f3. White aims to castle, play Nc3 or Re1 and slowly use the extra pawn. Black wants ...Bd6, short castling and a central push with ...e4 or ...Nf4, using the half-open b-file against b2. The pawn structure stays unbalanced and both sides have targets.

What the engine plays from here

Stockfish 17.1 at depth 20 rates the position +0.03: level. Its three top choices for Black:

  1. +0.03 6...c6 7.dxc6 bxc6 8.Bd3 Nd5 9.Nf3
  2. +0.36 6...Bd7 7.Qe2 Be7 8.Nf3 Nxd5 9.Nxe5
  3. +1.78 6...Nd7 7.Ne6 fxe6 8.dxe6 h5 9.Qf3

Pawns, from White's side.

How it scores on lichess

3,296 rated lichess games reached this position; White scored 47.8%.

under 120050.0%
1200–159943.8%
1600–199950.1%
2000 and up51.2%

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

Where it goes next

How to play against it

As Black, block with ...c6 and recapture with the b-pawn, accepting a second pawn deficit for open lines. Get ...Nd5 and ...Bd6 in fast and castle. The ...Nd7 block is a trap for Black: Ne6 breaks open the e8 king and wins material.

Questions

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

The Italian Game: Two Knights Defense, Polerio Defense, Bishop Check Line starts 1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Ng5 d5 5.exd5 Na5 6.Bb5+. Its ECO code is C58.

Is the Italian Game: Two Knights Defense, Polerio Defense, Bishop Check Line good for White?

Stockfish 17.1 rates the position +0.03 at depth 20, which is level. In 3,296 lichess games from our sample, White scored 47.8%. The main path for White in the Polerio, suited to players willing to defend a pawn plus against active Black pieces.

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

White checks on b5 before retreating, forcing Black to decide how to block. After ...c6 and the trade on c6, Black gets quick development and open lines for the extra pawn.

What should Black play next?

The engine's first choice is c6, with Bd7 and Nd7 close behind. ...c6 blocks the check with tempo on the bishop and opens lines after dxc6 bxc6.

Updated October 2026. Sources and method.