Chess Puzzle

Difficult Puzzle that I still need to know the reasons why...

I guess I can't say White to Checkmate but White to Win if played correctly..

Also if anyone can tell me who made this puzzle and the reason behind the moves... I know that black wants to give white the queen for stalemate.

black's king is trapped in the corner. with white's queen on the back rank, mate is threatened. whenever the king is moved, meaning that black can't gain time with a check. however, white's queen has to shake black's queen to gain mate, which it does with the check, then immediately moving to the back rank once again, where black can't do anything at all but delay the inevitable.

Its this: http://www.chess.com/forum/view/more-puzzles/puzzle-7-very-hard
I've posted it before. Check the move list. Thanks =)

Why not

2. Qa3

If you mean for black, then 3. Kd8+ Qf8 4. Qxf8#

Never mind I figured it out.