The Bishop's Opening – Calabrese Counter-Gambit arises after 1.e4 e5 2.Bc4 f5. ECO code: C23.

Named after Greco Calabrese. Black immediately strikes at the e4-pawn, but 2...f5 weakens the kingside severely. After 3.d3 or 3.Nf3, White can exploit the weakened e8–h5 diagonal. The counter-gambit is considered dubious.