Chess puzzle (Advantage)
Opening: Grunfeld_Defense, Grunfeld_Defense_Exchange_Variation
Moves: 1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. cxd5 Nxd5 5. e4 Nxc3 6. bxc3 Bg7 7. Bc4 c5 8.
Ne2 Nc6 9. Be3 O-O 10. O-O cxd4 11. cxd4 b6 12. Rc1 Bb7 13. Bd5 Rc8 14. Qa4 Qd7
15. Rfd1 Rfd8 16. Qb3 e6 17. Bc4 *
Position (FEN): 2rr2k1/pb1q1pbp/1pn1p1p1/8/2BPP3/1Q2B3/P3NPPP/2RR2K1 b - - 1 17
Black to move.
Themes:  Middlegame  
Puzzle rating: 1397
Best move: Na5