yes an interesting puzzle
first i looked at trying to use the queen/bishop to push the king into a mating position but just dosnt come up within 3 moves. but the zuzwang with whites king is a nice move
but why wouldnt black go 1.c8, doesnt this delay the mate?
No. After Kc8, the end result is the same because white plays Qb6! and the same position arises.
Really good and educational... I realize this was composed, but opportunities for creating zugzwang (the way the Queen takes away all the king's squares with 2.f6) are much more common in OTB play than one might initially think. But If you don't know to look for them, you never see them!
If you guys liked this puzzle, be sure to check out the other puzzles I've posted :D they all have interesting themes, although perhaps too many of them involve underpromotion,
White mates in three. This is quite an interesting one!