Chess puzzle (Advantage)
Opening: Semi-Slav_Defense, Semi-Slav_Defense_Main_Line
Moves: 1. d4 Nf6 2. c4 e6 3. Nc3 d5 4. e3 c6 5. Nf3 Bd6 6. Ne5 Nbd7 7. f4 O-O 8. Bd3
Qc7 9. O-O b6 10. a3 Bb7 11. b4 dxc4 12. Bxc4 c5 *
Position (FEN): r4rk1/pbqn1ppp/1p1bpn2/2p1N3/1PBP1P2/P1N1P3/6PP/R1BQ1RK1 w - - 0 13
White to move.
Themes:  Middlegame  
Puzzle rating: 1876
Best move: Nb5