Checkmate in 1, not that hard though

someone ask the OP whether or not enpassant is legal in this position.

The OP may honestly not know. The OP may only know if c7-c5 was the previous move, not whether or not the ensuing ep capture is "legal".

sorry, i made a mistake making the analysis

it WAS supposed to be en passant, but i forgot to remove the bishop

Ok, so the OP has confirmed that the intended solution is e.p. capture. And you know what? If this could be proven as the only move, I would consider this a pretty good puzzle. Alas, this cannot be proven, and thus it is not a valid puzzle. Just because the forum title is “mate in one” doesn’t mean that a mate exists. That’s like saying that if I made a forum called “There are ten hours in a day in Alabama” then an Alabaman hour would be redefined as one tenth of a day.

Well his testimony is good enough for me. That's proof it is, and was, an en passant theme position. But it wasn't really necessary. The title of the topic itself is strong evidence there could be a checkmate somewhere. Early on I mentioned that it was a mate, just not in one. It looks to me like he confirmed that the black bishop was overlooked, so it indeed was not a mate in one. A pretty simple mistake that doesn't really detract from the purpose of the position.

PS: I'm not sure what to make of your Alabama situation. Other than there ARE in fact 10 hours in a day in Alabama.