Two knights defence (Modern bishop's opening)
1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. d3
White advances the king's pawn to e4. Black pushes the king's pawn to e5. White develops the knight to f3.
Black develops the knight to c6. White develops the light-squared bishop to c4. Black moves the knight to f6.
White moves the queen's pawn to d3.