King's Gambit Accepted - Keres (Mason-Steinitz) gambit
1. e4 e5 2. f4 exf4 3. Nc3
White moves the king's pawn to e4. Black moves the king's pawn to e5. White plays the f-pawn to f4.
Black captures on f4 with the king's pawn. White develops the knight to c3.