Chess puzzle (Advantage)
Opening: Queens_Gambit_Declined, Queens_Gambit_Declined_Marshall_Defense
Moves: 1. d4 d5 2. c4 Nf6 3. cxd5 Qxd5 4. Nc3 Qa5 5. Bd2 Qb6 6. Qc2 Qxd4 *
Position (FEN): rnb1kb1r/ppp1pppp/5n2/8/3q4/2N5/PPQBPPPP/R3KBNR w KQkq - 0 7
White to move.
Themes:  Opening  
Puzzle rating: 1909
Best move: Nb5