Puzzle by Normajean Yates

I found, quite nice really. Dun use chess computers!

White to play, mate in four:

all my instincts tell me there is no forced mate in 4 possible.

oh sure, there is.

ah i see it now, its all working with pins. nice.

got it. took me quite a while.

I think I have the first couple of moves, but I can't quite see how to finish it off.

What I have determined is that white must continually check black, else black will launch a counterattack and white won't be able to do it in 4.

The queen on f seems like the best launching point, as there are two queens attacking it and it does give check.

1) Qaxf2 Qgxf2 2) Qfxf2 Qhxf2 3) ???

This is where I get stuck as to how to continue.

Oh idiot that I am, I just found the solution and have PM'd doodinthemood a full solution.

I was mistaken on my second move, although in my estimation any series of moves where you keep his king in check should suffice for a clear win.

geep has it, as does heinzkat.

What is this? The non-sub club?

forkedknight also has the answer. He basically had it the same time as the others, but he blundered a bit in his writing it down.