Chess puzzle (Checkmate)
Opening: Queens_Gambit_Declined, Queens_Gambit_Declined_Janowski_Variation
Moves: 1. d4 d5 2. c4 e6 3. Nc3 a6 4. Nf3 dxc4 5. a4 Nc6 6. e4 Na5 7. Bf4 f6 8. d5 Bb4
9. Be2 exd5 10. Qxd5 Qxd5 11. exd5 Kd8 12. O-O-O Bf5 13. Nd4 Bg6 14. Ne6+ Kc8
15. Bxc7 *
Position (FEN): r1k3nr/1pB3pp/p3Npb1/n2P4/Pbp5/2N5/1P2BPPP/2KR3R b - - 0 15
Black to move.
Themes:  Middlegame Mate in 1 
Puzzle rating: 761
Best move: Nb3#