Lion Defense: Anti-Philidor, Lion's Cave

The Lion Defense: Anti-Philidor, Lion's Cave is a chess opening classified under ECO code B07 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 d6 2. d4 Nf6 3. Nc3 Nbd7 4. f4 e5. The resulting position leaves white to move.