two knights defence - Ulvestad variation
1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. Ng5 d5 5. exd5 b5
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 moves the knight to f6.
White moves the knight to g5. Black plays the queen's pawn to d5. White captures on d5 with the king's pawn.
Black advances the b-pawn to b5.