Pterodactyl Defense: Sicilian, Unpin

The Pterodactyl Defense: Sicilian, Unpin is a chess opening classified under ECO code B27 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 5 moves: 1. e4 c5 2. Nf3 g6 3. d4 Bg7 4. Nc3 Qa5 5. Bd2. The resulting position leaves black to move.