Illegal Position Contest!

You noticed! I was hoping people would trust that it was from white’s POV

Most people know by now to check the coordinates on your positions.

Bishops in the corners can’t get there

After black retracts a capture, white has no possible last move.

That position reminded me of another recent position, and since I am running out of ideas for illegal positions, I'll just repost it if you'd like to see.

At #8224 I said "Most people know", not "All people know".

I don't remember this one. How long ago was it posted? Anyway, I decided to try making a proof game and the closest I could get is this game where Black needs one more move to get the last knight into place. It's not an ironclad illegality proof, but I don't see any way to improve.

The position was posted around 13 days ago.

White needs a tempo move to allow the black position to be set up. Both the b and c pawns must have already moved, so the only possible way is for black to have captured a white piece, which isn't possible because white already used all 3 extra pieces to set up black's pawns, and none of those pawns has an available uncapture.

That's a little too obvious. White has eight promoted rooks and still has a pawn on the board.

I found it and discovered I had already given an illegality proof. I probably need some of those memory pills a guy on TV keeps asking me to buy.

Last move has to be an en passant on g6, otherwise the black king is in an impossible check. Before that, black’s original dark squared bishop was captured at home, so both dark squared bishops are promoted and both black pawns had to promote. White’s bishop is also promoted due to unmoved pawns at d2 and b2. The pawn had to promote on either b8 or d8. In order for the knight to get to c8, b6 had to happen before cxd6 to let the light squared bishop out and get the knight to c8 from d6. However the dark squared bishop would be trapped. Hence illegal. I hope I’m not missing anything.

While you were writing your illegality proof, I was writing mine. They're both the same, so I don't think you're missing anything. Here's what I wrote.

White's only legal way for the bishop to give check while reaching the end position is for White to retract Pf5xg6 e.p., uncapturing a black pawn that has just played Pg7-g5. The g7 pawn making Black's last move means that the f8 bishop was captured at home, and both dark-squared black bishops are promoted, so the bishop at h7 is the original c8 bishop. Black had to previously play Pb7-b6 before Pc7xd6, so the c8 bishop could move and a black knight could reach c8. That means the promoted white bishop could never have escaped from the 7th and 8th ranks, but has illegally returned to e3. (The c1 bishop never moved and was captured at home, so the white bishop on the board must have promoted.)

Why did you say not sorry? Both kings in check, a bit too obvious

Stop whining about the obviousness of it already. It's interesting to analyze these types of positions in terms of who is winning or not.

I wouldn’t say I was whining. In his position it is obvious black is winning. In yours I suspect white is but I am not sure.