two knights defence - Wilkes Barre (Traxler) variation
1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. Ng5 Bc5
White plays 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 jumps the knight to f6.
White jumps the knight to g5. Black develops the dark-squared bishop to c5.