Chess Opening Theory/1. e4/1...e5/2. Nf3/2...d6/3. d4/3...Nc6

3...Nc6
This move is uncommon, as the pin /4. Bb5/ is annoying, yet, White is only a little better.

Another popular choice for White is /4. dxe5/, which is best met with 4...Nxe5 or 4...dxe5. Either way, Black will lose castling rights after Qxd8+.

Stockfish prefers /4. d5/, which attacks the knight and forces it to move backwards.

Various transpositions are possible:
 * 4. Nc3 transposes to the Three Knights Opening.
 * 4. Bc4 transposes to the Semi-Italian Opening.
 * 4. c3 transposes to the Ponziani Opening.