Chess puzzle (Checkmate)
Opening: Nimzo-Larsen_Attack, Nimzo-Larsen_Attack_Classical_Variation
Moves: 1. b3 d5 2. Bb2 c6 3. f4 Nf6 4. Nf3 Bf5 5. e3 e6 6. h3 Bd6 7. g4 Bg6 8. g5 Ne4
9. Bxg7 Rg8 10. Bb2 Bh5 11. Nc3 Nxg5 12. fxg5 Qxg5 13. Nxg5 *
Position (FEN): rn2k1r1/pp3p1p/2pbp3/3p2Nb/8/1PN1P2P/PBPP4/R2QKB1R b KQq - 0 13
Black to move.
Themes:  Middlegame Double Bishop Mate, Mate in 1 
Puzzle rating: 868
Best move: Bg3#