Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...d6/4. Nc3

= Paris Defence =

4. Nc3
The move 4. Nc3 develops the knight and protects the pawn on e4 from any possible attack. Note that this is not the best move but still solid.

'''1. e4 e5 2. Nf3 Nc6 3. Bc4 d6 4. Nc3'''