Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Nf6/4. Ng5/4...d5/5. exd5/5...Na5

= Two Knights Defence: Polerio Defense =

5...Na5
Attacking the bishop, yet moving to the side of the board. In theory this is Black's best move, but it's not that clear.

Theory table
.
 * 1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Ng5 d5 5.exd5 Na5

Statistics
Estimated next move popularity Bb5+ 87.4%, d3 11.9%, b3 0.7%