King's Gambit Accepted - Hanstein gambit
1. e4 e5 2. f4 exf4 3. Nf3 g5 4. Bc4 Bg7 5. O-O
White plays the king's pawn to e4. Black pushes the king's pawn to e5. White advances the f-pawn to f4.
Black captures on f4 with the king's pawn. White develops the knight to f3. Black plays the g-pawn to g5.
White develops the light-squared bishop to c4. Black develops the dark-squared bishop to g7. White castles kingside.