Sicilian Defense: Smith-Morra Gambit Declined, Dubois Variation

The Sicilian Defense: Smith-Morra Gambit Declined, Dubois Variation is a chess opening classified under ECO code B21 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. d4 cxd4 3. c3 d3 4. c4. The resulting position leaves black to move.