Chess puzzle (Checkmate)
Opening: Pirc_Defense, Pirc_Defense_Kholmov_System
Moves: 1. e4 g6 2. d4 Nf6 3. Nc3 d6 4. Bc4 Bg7 5. Be3 O-O 6. Qd2 c6 7. Bh6 b5 8. Bxg7
Kxg7 9. Bb3 a5 10. a3 Ba6 11. O-O-O Qb6 12. f3 b4 13. axb4 axb4 14. Na4 Bb5 15.
Nxb6 *
Position (FEN): rn3r2/4ppkp/1Npp1np1/1b6/1p1PP3/1B3P2/1PPQ2PP/2KR2NR b - - 0 15
Black to move.
Themes:  Middlegame Back Rank Mate, Mate in 1 
Puzzle rating: 777
Best move: Ra1#