Chess puzzle (Advantage)
Opening: French_Defense, French_Defense_Advance_Variation
Moves: 1. e4 e6 2. d4 d5 3. e5 c5 4. c3 Nc6 5. Nf3 Qc7 6. Bd3 cxd4 7. cxd4 Nge7 8. Nc3
a6 9. O-O Qd8 10. a3 Nf5 11. Bxf5 exf5 12. Qb3 Be6 13. Qxb7 *
Position (FEN): r2qkb1r/1Q3ppp/p1n1b3/3pPp2/3P4/P1N2N2/1P3PPP/R1B2RK1 b kq - 0 13
Black to move.
Themes:  Middlegame  
Puzzle rating: 1573
Best move: Na5