What is an example of a very difficult one-move checkmate? Usually one-move checkmate puzzles are easy. However, I am wondering if there is a relatively more difficult one-move checkmate puzzle. Here are a few thoughts:


There are many legal moves. 
One or several legal moves are tempting but incorrect. Especially under time pressure, an inexperienced player tends to choose such a "wrong" move.
Finding the checkmate move requires some out-of-the-box thinking. It is a move that most players will not normally consider, expecially under time pressure.


Anyone knows a good "difficult" one-move chekmate problem?
Very difficult is relative and given enough time players of most strength should be able to find a mate in one.

I don't have a concrete example, but in my view the following features would make it more difficult (some of these exclude each other):


a large number of possible moves (i.e. lots of pieces on the board and an open position)
the mating move is done by a piece moving to the back (towards the mating player)
it is a non-standard mate (not one you have seen before in your tactics excercise, but rather of a studies type)
the mating move is a move where the moving piece uncovers a piece that helps in the check mate (either by taking away squares from the king, or more tricky by pinning a possible defender)
lots of pins are involved that prevent defenders from defending
there are tempting moves that don't work for not-too-obvious reasons
the move is an en passant capture or an underpromotion or castling
(not sure this counts) the mate requires retrograde analysis to prove that en passant capture is allowed or that castling is allowed
large distances are involved, both in the move itself and in the attacking of the king (say moving a queen from h8 to a1 to check mate a king on a8 might not be that obvious)
the position is such that the pawns move unexpectedly in a direction you would not expect (down, left, right)
asking for a mate in one  for black (without specifying that it is black's move) This can be particularly tricky if it looks as if white could mate as well.