The pinned knight on f6 is the key to this most basic DDG combination. The following moves are surprisingly forcing: 11.Ne5 Nbd7 12.Nxd7 Qxd7 13.Bxf6 gxf6 14.Bxh7+ Kxh7 15.Qh5+ Kg7 16.Qg4+ Kh8 17.Rxf6 Kh7 18.Qg5 Rh8 19.Rh6# 1-0, Heikkinen - marco, Zone 1996.