Chess puzzle (Checkmate)
Opening: Slav_Defense, Slav_Defense_Three_Knights_Variation
Moves: 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 Bf5 5. cxd5 cxd5 6. Qb3 Qb6 7. Qxb6 axb6 8.
Bf4 Nc6 9. Nb5 O-O-O 10. e3 Ne4 11. Rc1 Bd7 *
Position (FEN): 2kr1b1r/1p1bpppp/1pn5/1N1p4/3PnB2/4PN2/PP3PPP/2R1KB1R w K - 3 12
White to move.
Themes: Pin Opening Mate in 1 
Puzzle rating: 983
Best move: Na7#