The Rat Defense: Fuller Gambit is a chess opening classified under ECO code B00 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 3 moves: 1. e4 d6 2. f4 d5 3. exd5 Nf6. The resulting position leaves white to move.
Resulting Position
1. e4 d6 2. f4 d5 3. exd5 Nf6
rnbqkb1r/ppp1pppp/5n2/3P4/5P2/8/PPPP2PP/RNBQKBNR w KQkq - 1 4Resulting Position