Chess puzzle (Checkmate)
Opening: Queens_Pawn_Game, Queens_Pawn_Game_Mason_Variation
Moves: 1. d4 d5 2. Bf4 Nf6 3. e3 Nc6 4. Nd2 Bf5 5. c3 e6 6. h3 Bd6 7. Ngf3 Bxf4 8.
exf4 Ne4 9. Ne5 Qh4 10. Nxe4 Bxe4 11. Nxc6 bxc6 12. Qd2 Rb8 13. O-O-O Qe7 14.
c4 Qa3 15. bxa3 *
Position (FEN): 1r2k2r/p1p2ppp/2p1p3/3p4/2PPbP2/P6P/P2Q1PP1/2KR1B1R b k - 0 15
Black to move.
Themes:  Middlegame Mate in 1 
Puzzle rating: 550
Best move: Rb1#