this was about as hard as a satsuma
I know how insanely difficult it is to mate in one move. But, it's not impossible!
There is no mate in 1 there is only 1 check rxa7 and that's not checkmate
Stock fish also can't see mate
In this position, it's not possible to mate in one move.
Exactly
There was a mate in one move for black in the position I originally set up for this topic
castle I think?
Yes. Black has to castle if he wants to checkmate white!