This is a fine helpmate-in-five by CJ Feather: Black moves first and both sides conspire to reach a position in which Black is mated after five moves by each player.

The only feasible mate is with Black men on a4 and b4 and White's knight moving from g6 to e5 and c4. The problem is what to do with White's other three moves. His knights cannot lose a move, and the king is desperately short of moves. The answer is extraordinary: 1.Ra5 Ne5 2.f1=R+! Kh2 3.Be1 Kxh3 4.Bb4 Kxh4 5.Ra4 Nc4 mate!

Note how Ne5 must come before Kh2 (to block the line of the black queen) and Bb4 must come in time to let the king move from h3 to h4 (which is why 1...Rc4 is wrong). Finally, the pawn must promote to a rook - nothing else works. An elegant and unusual composition.