Chess puzzle (Checkmate)
Moves: 1. d4 d5 2. c4 Nf6 3. cxd5 Nxd5 4. e4 Nf6 5. Nc3 Bg4 6. Qb3 Qxd4 7. Qxb7 e5 8.
Bb5+ Nfd7 9. Bxd7+ Kxd7 10. Qxa8 Bb4 11. Qd5+ Qxd5 12. exd5 Rd8 13. Bd2 Na6 14.
Nge2 Nc5 15. O-O-O Nd3+ 16. Kc2 Nxf2 17. Rdf1 Nxh1 18. Rxh1 Bf5+ 19. Kb3 Rb8
20. Kc4 Bd6 21. b3 *
Position (FEN): 1r6/p1pk1ppp/3b4/3Ppb2/2K5/1PN5/P2BN1PP/7R b - - 0 21
Black to move.
Themes:  Middlegame Mate in 1 
Puzzle rating: 862
Best move: Rb4#