King's Gambit Declined - classical counter-gambit
1. e4 e5 2. f4 Bc5 3. Nf3 d6 4. c3 f5
White moves the king's pawn to e4. Black moves the king's pawn to e5. White advances the f-pawn to f4.
Black develops the dark-squared bishop to c5. White develops the knight to f3. Black advances the queen's pawn to d6.
White advances the c-pawn to c3. Black plays the f-pawn to f5.