Sicilian Defense: Big Clamp Formation

The Sicilian Defense: Big Clamp Formation is a chess opening classified under ECO code B20 in the Semi-Open Games family, where Black responds to 1.e4 with something other than 1...e5, including the Sicilian Defense, Caro-Kann, and Pirc. It is reached after 4 moves: 1. e4 c5 2. d3 Nc6 3. c3 d6 4. f4. The resulting position leaves black to move.