Bishop's Opening: Calabrese Countergambit, Jaenisch Variation

The Bishop's Opening: Calabrese Countergambit, Jaenisch Variation is a chess opening classified under ECO code C23 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 3 moves: 1. e4 e5 2. Bc4 f5 3. d3. The resulting position leaves black to move.