About this opening
Italian Game: Two Knights Defense, Polerio Defense is an opening in the Encyclopedia of Chess Openings,
classified under code C58. ECO group C (C00–C99)
covers open games (1.e4 e5) and the French Defence, including the Ruy Lopez, Italian, Scotch and King's Gambit. This particular variation is reached
after 10 half-moves from the
starting position, with the move sequence 1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. Ng5 d5 5. exd5 Na5.
It belongs to the Italian Game family.
Within that family this is a level-2 branch (the Two Knights Defense → Polerio Defense line). The immediate parent line is Italian Game: Two Knights Defense, transitioned via 5…Na5.
The opening sequence in prose form: 1.e4 e5, 2.Nf3 Nc6, 3.Bc4 Nf6, 4.Ng5 d5, 5.exd5 Na5. From this position 2 named continuations are recorded in the encyclopaedia, each leading to a distinct theoretical line.
Use the interactive board above to walk through the moves position-by-position. Click any move in the navigation to step backwards, or use the keyboard arrow keys. The list of recorded continuations sits directly below the board. For statistical data — how often master-level players have reached this position, White's win-rate, draw frequency, Black's score — see the panel in the right column.
Caissly's coverage of C58 extends through every named sub-variation in this line and across all four locales (English, Spanish, Portuguese, Russian). Where editorial commentary exists for a specific variation it appears as the page body; otherwise the page presents the structural data, board, and statistics as shown here.