The solution is 1 Rxf7+!! Kxf7 2 Bxg6+ Kg7 3 Qf6+ Kh6 (or Kg8 4 Qf7+ Kh8 5 Qh7#) 4 Bf5+ Kh5 5 Qg6+ Kh4 6 g3# is mate and if 2...Kg8 then 3 Bh5+!! Kh7 4 Qg6+ Kh8 5 Qf6+ Kg8 6 Bf7+ Kh7 7 Bg6+ and we have the same position leadig to mate.