Chess puzzle (Checkmate)
Opening: Grunfeld_Defense, Grunfeld_Defense_Stockholm_Variation
Moves: 1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. Bg5 Ne4 5. Nxe4 dxe4 6. e3 Bg7 7. Ne2 c5 8.
Qa4+ Bd7 9. Qb3 Qa5+ 10. Kd1 cxd4 11. Qxb7 Bc6 *
Position (FEN): rn2k2r/pQ2ppbp/2b3p1/q5B1/2Ppp3/4P3/PP2NPPP/R2K1B1R w kq - 1 12
White to move.
Themes:  Middlegame Mate in 1 
Puzzle rating: 1213
Best move: Qxe7#