Hardest mate in 1 puzzles

M2
cxb6+ c5 Bxc5#
c6+ Qc5 Bxc5#
1.cxb6+ not possible, there is no proof that Black's last was ...b7-b5.
1.c6+ is fine, and mate next move.
For some reason, a crapload of useless pieces are planted at the board.
M2
cxb6+ c5 Bxc5#
c6+ Qc5 Bxc5#
1.cxb6+ not possible, there is no proof that Black's last was ...b7-b5.
1.c6+ is fine, and mate next move.
For some reason, a crapload of useless pieces are planted at the board.
This one is a joke that I posted on this site earlier, but I'd like to post it here again. White to move and mate in 1.
You may read the FIDE Laws of Chess carefully to solve this. I think the idea behind this joke problem is still sound under current rules taking effect from 1 January 2023, unlike some famous ones, e.g. promotion into an opponent's piece or a piece already on the board, castling with a promoted rook, parrying the check by putting one's king in triple check, etc. which have all been fixed in the later versions of FIDE rules.