1.Bxg6? threat 2.Sd3# [A]

1...Rd1[x]/Re4[y] 2.Re4#

1...Re3!

1.Bf5? threat 2.Qxc5# [D] (2.Sd3?)

1...gxf5 2.Sd3# [A]

1...Kxf5 2.Qf6# [B]

1...Rd1![x]

1.Rf4? threat 2.Sg4# [C]

1...Re4![y]

1.Rd4! threat 2.Qf6# [B] (2.Sg4?)

1...cxd4 2.Sg4# [C]

1...Kxd4 2.Qxc5# [D]

Threats of two phases (AB, CD - two pairs) became mates in the third phase  after black defences that are possible as a result of its first moves (1.Bf5? or 1.Rd4!)

Pseudo le Grand (DB-BD). Clearance sacrifices. Threat correction.