King's Gambit Accepted - Cunningham defence
1. e4 e5 2. f4 exf4 3. Nf3 Be7
White moves the king's pawn to e4. Black plays the king's pawn to e5. White pushes the f-pawn to f4.
Black captures on f4 with the king's pawn. White develops the knight to f3. Black develops the dark-squared bishop to e7.