King's Gambit Declined: Classical Variation, Rubinstein Countergambit

The King's Gambit Declined: Classical Variation, Rubinstein Countergambit is a chess opening classified under ECO code C30 in the Open Games & French Defense family, beginning with 1.e4 e5 or 1.e4 e6, including the Italian Game, Ruy Lopez, and French Defense. It is reached after 4 moves: 1. e4 e5 2. f4 Bc5 3. Nf3 d6 4. c3 f5. The resulting position leaves white to move.