Illegal Position Contest!

#8237, that's one of the best ones ever, with the exception that it's black to move. Please flip the colors of the pieces so white is the one in check, thank you!

Here is an illegal position by n95 that EndgameEnthusiast believes is the best one ever. Can you find the illegality?

Personally if black is in check, I think the software should have it automatically as black to move rather than white to move.

No it should only require two, capture on f7 from g6 before black goes g5

What I mean is white only requires 3 captures

No there could be a capture with the pawns on h7, f6, and g7 with hxg6 and gxf7

It has nothing to do with the capture count, or the cramped upper kingside. It does have to do with subtle indirect combinations of these things though! That's all I'm gonna say because I don't want to ruin the genius of it, at first I thought it was impossible to get the pieces where they were on the kingside but that isn't it. I'll give the same hint that the person gave with this one, the pawn being on a4 instead of a3 makes it illegal.

White has four promoted bishops but is only missing two pawns.

#8256 The H1 bishop

Not possible

Black also has 3 knights but 7 pawns leaving only 1 pawn available to promote on h1 for the bishop, but you need another pawn for the 3rd knight.

Both kings in check

Same reason as given at #8222.

(Turnabout is fair play.)

A little too obvious. Pawn at h3 has made a ninja move.

I was hoping that trick would work again. I wonder what the shortest proof game in the correct orientation would be.

Black's got all his pieces but one of White's b and c pawns seems to have taken something.