Back to orthodox chess, with a logical more-mover which should not prove
too difficult.
White can try 1.Qa8 (threat 2.Qd8 mate) Ba5 2.Qe8 (threats 3.Qh5 and
3.Qe7 mate) but 2...Rc5 is an adequate defence.
The key, 1.Sf2 (threat 2.Rg4 mate) decoys the black bishop,
leading to 1...Bxf2 2.Qa8 Bb6 3.Qe8 Rc5 4.Qe1 mate. Other defences
lead to short mates, for example 1...Se5 2.Sg2+ Kh4 3.Qh4. This
type of decoy, where a good defence by a piece is replaced by a bad
defence by the same piece after it is decoyed, constitutes the Roman
theme.
Darko Šaljić: Beautiful postponed “Umnov” on e1.