Chess puzzle (Checkmate)
Moves: 1. Nf3 d5 2. c4 c6 3. Nc3 Nf6 4. Qa4 e6 5. e3 Bd7 6. Ne5 b5 7. cxb5 cxb5 8.
Nxb5 Bd6 9. Nxd6+ Kf8 10. Nxd7+ Qxd7 11. Qxd7 Nbxd7 12. Bb5 Ke7 13. Nb7 Rab8
14. Bxd7 Nxd7 15. Na5 Rhc8 16. O-O Nc5 17. d4 Nd3 18. Rd1 Nxb2 19. Bxb2 Rxb2
20. Rdc1 Rxc1+ 21. Rxc1 Rxa2 22. Rc7+ Kd6 23. Rxa7 *
Position (FEN): 8/R4ppp/3kp3/N2p4/3P4/4P3/r4PPP/6K1 b - - 0 23
Black to move.
Themes:  Endgame Back Rank Mate, Mate in 1 
Puzzle rating: 644
Best move: Ra1#