Giuoco Pianissimo
1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. d3 Nf6
White plays the king's pawn to e4. Black plays 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 develops the dark-squared bishop to c5.
White plays the queen's pawn to d3. Black moves the knight to f6.