Chess puzzle (Advantage)
Opening: Sicilian_Defense, Sicilian_Defense_Marshall_Gambit
Moves: 1. d4 e6 2. e4 d5 3. Nc3 c5 4. exd5 exd5 5. dxc5 d4 6. Ne4 Qe7 7. f3 *
Position (FEN): rnb1kbnr/pp2qppp/8/2P5/3pN3/5P2/PPP3PP/R1BQKBNR b KQkq - 0 7
Black to move.
Themes:  Opening  
Puzzle rating: 1715
Best move: f5