Checkmate in 1, not that hard though

I don't see a mate. What's the solution to the puzzle?

There is no mate of any kind.

It's checkmate alright. Just not in one.

Where's the mate?

Solved it! 1. Q@h6#!

As long as we are treating it as bughouse with additional pieces being dropped in, R@h6# and N@c4# would also work.

My best guess is that this was supposed to be another e.p. puzzle but the O.P. didn't realize that dxc6e.p.+ was not mate because of Black Bd4 (interposing).

If en passant is allowed dxc6# is mate

Then it woould be more of a riddle than a puzzle. Also that's not mate because of Bd4

Clicking analysis reveals that en passant is not alegal move, so that is not correct.

Empassant is a right move

Repeating the comment from my post 9 hours ago, even if en passant was a valid move it still fails as a mate in one because the Black Bishop can be moved to block the discovered check.

Why isn't en passant a legal move? It's still checkmate, just not in one.

En passant is only legal if black's last move was c7-c5. There's no proof that this would be the case here. Therefore e.p. is not legal.

I wouldn't say that makes it illegal. I would say it makes it the ONLY possible move given the conditions of imminent checkmate. I don't see anything in the puzzle that prevents the move c7-c5, or anything that indicates an illegal position or illegal moves. In chess, an illegal move is one that violates the rules of chess. Which rule of chess does the move c7-c5 (or the ensuing en passant) violate?

I'm sure we could take a billion three hundred million trillion three hundred million positions where there was no proof of what the last move was. That doesn't make them illegal.

I would say that every possible legal move must be considered, and since there is no proof that pawn move WASNT played it must be considered as well.

No mate in one

I think most people have figured that out by now. He should have said mate in two.