Chess puzzle (Checkmate)
Opening: Queens_Gambit_Declined, Queens_Gambit_Declined_Queens_Knight_Variation
Moves: 1. d4 d5 2. c4 e6 3. Nc3 f5 4. e3 c6 5. cxd5 cxd5 6. Bb5+ Bd7 7. Qa4 Nc6 8. Nf3
Nge7 9. Ne5 Nxe5 10. Bxd7+ Nxd7 11. O-O g6 12. Nb5 a6 *
Position (FEN): r2qkb1r/1p1nn2p/p3p1p1/1N1p1p2/Q2P4/4P3/PP3PPP/R1B2RK1 w kq - 0 13
White to move.
Themes:  Opening Mate in 1 
Puzzle rating: 831
Best move: Nd6#