Chess puzzle (Advantage)
Opening: Indian_Defense, Indian_Defense_Colle_System
Moves: 1. d4 Nf6 2. Nf3 d6 3. e3 g6 4. Bd3 Bg7 5. O-O e5 6. c3 e4 7. Bb5+ Bd7 8. Bxd7+
Qxd7 9. Nfd2 d5 10. h3 O-O 11. b4 Nc6 12. Ba3 Ne7 13. Qb3 Rab8 14. b5 c6 15.
bxc6 bxc6 16. Qa4 Rfe8 17. Nb3 Qb7 18. Nc5 Qc7 *
Position (FEN): 1r2r1k1/p1q1npbp/2p2np1/2Np4/Q2Pp3/B1P1P2P/P4PP1/RN3RK1 w - - 6 19
White to move.
Themes:  Middlegame  
Puzzle rating: 1309
Best move: Na6