Chess puzzle (Advantage)
Opening: Kings_Indian_Attack, Kings_Indian_Attack_Sicilian_Variation
Moves: 1. Nf3 d5 2. g3 c5 3. d4 c4 4. Bg2 Nf6 5. Nc3 Nc6 6. O-O Bf5 7. Re1 e6 8. Bf4
a6 9. b3 Nb4 10. Rc1 b5 11. a3 Nc6 12. Nh4 Nh5 13. b4 *
Position (FEN): r2qkb1r/5ppp/p1n1p3/1p1p1b1n/1PpP1B1N/P1N3P1/2P1PPBP/2RQR1K1 b kq - 0 13
Black to move.
Themes:  Middlegame  
Puzzle rating: 1187
Best move: Nxf4