Chess puzzle (Advantage)
Opening: Queens_Gambit_Declined, Queens_Gambit_Declined_Albin_Countergambit
Moves: 1. d4 d5 2. c4 e5 3. dxe5 Ne7 4. Nf3 h6 5. Nc3 c6 6. Bf4 Na6 7. a3 Be6 8. cxd5
Nxd5 9. Nxd5 Bxd5 10. e3 Qa5+ 11. b4 *
Position (FEN): r3kb1r/pp3pp1/n1p4p/q2bP3/1P3B2/P3PN2/5PPP/R2QKB1R b KQkq - 0 11
Black to move.
Themes:  Middlegame  
Puzzle rating: 1719
Best move: Nxb4