Hardest Checkmate in 1

Pawn E6 using the en passant rule

This position is impossible. The white pawns took two black pieces, but Black has 15 pieces. 

That is true and has been noted before. Some will take it as an excuse to play the e.p. move. After all, you can't prove anything about the past game in an illegal position, so why not permit every e.p. move by default agreement? In my view, the sum of such artificial elements classifies the challenge as a joke problem.

Btw, this is how you identify joke problems. You assume there must be a solution to the challenge and then you start tweaking the rules until you find an elegant combination of solution and rules. The current joke problem is rather awkward as (a) it is not very imaginative (b) it's not announced as a joke problem (c) uneducated solvers will struggle with e.p. and castling moves in puzzles for the rest of their lives when they take this one seriously!

thats too ez

\

Only if I'd known blacks last move is e5, Answer is #e6.

Please, next time post a puzze whereas we all can see the last move played e.g.:

I see a mate in one. If the last move was pawn to e5 for black, En Passant would discovered checkmate the black king on that move with the bishop.

I may have seen this thread and posted this before, but here's a position where blacks move had to have been g7-g5, so en passant can be proven to be possible, and it's mate in 2 right after. In a similar matter, the following mate in 2 below, it can be proven that black doesn't have the right to castle:

If it's white to move, 1. dxe6 e.p. might work if black's last move was e5.

That seems to me to be the only solution.

However, generally, whenever given a puzzle position like this, it is considered the starting position, thus there have not been any moves played yet.
Therefor, this puzzle's solution is mid at best;

I analyzed the board and it is mate in 2

aha, after 251 comments you found a new solution?

If the coordinates weren't shown the board could be upside down, then bxe5 would be mate, but the position would be totally illegal and impossible. I think even the position now is impossible. There aren't enough pieces taken to account for the doubled pawns.

I agree with you this can't be from a real chess game as black has too many pieces. But the meaning and purpose of the puzzle is still there (in comment #248 you see the last move black has played), even if the chess composer didn't think much of it - my opinion --> bad puzzle, but the purpose (taking into consideration) of the puzzle is ok (which doesn't mean it should be integrated in chess.com puzzles obviously).

Can Pe5 be taken en passant?

Having read the preceding 255 posts, is that the best question you can come up with?

I didn't read all 255 comments

@jroch 

Fair enough, but they really should only be permitted if it can be proven that either en passing or casting is possible.

Qf6#

this isn't correct. After Qf6+ then Kxh6

Forgivable, but the 250 you did read provided all the answers you want to hear and did never want to hear