Shortest-proof-game challenge

With black to move (if I did this correctly) white only has one legal previous move. If not, someone better can probably fix it. If this isn't legal I'll be annoyed.

@5749
Last move Bf6-h8
Again this is an illegal position.
Black pawns must have captured white men on c6 and e6. Bf1 must be captured.
Thus 3 white men captured.
3 white men are missing: Bf1, h2, and a rook.
Bf1 must be captured on its starting square.
Rh1 could have moved to either c6 or e6 to be captured by a black pawn.
Pawn h2 could have moved to e6 to get captured, but only if it captured 3 black men to get there.
Black has still 14 men on the board, only 2 are missing: a rook and a queen.
That is not enough for pawn h2 to reach e6 to get captured.
Hence illegal.

I was under the impression h2 could've taken the queen on g5, the rook on h6, promoted, and moved to e6.

Yes, there are various ways. The plus for the Reflexmate type is that it is standard type. This is more attractive from a community perspective where people compare and build on one another's constructions. Special conditions raise the suspicion they were added to fix a bug , not as a beauty spot

Perhaps we could put BishopTakesH7's condition into a new standard type called the Suspicious type. It would give us the plus of a standard type for any previously nonstandard condition.

Ah but in this version it's a Rook on b3, with a pawn on b3 is it legal?

@5755
Yes, you are right. With a rook on b3 legal, with a pawn on b3 illegal.

Wrong!

See recent posts in Topic "Illegal Positions Contest"

@5757

And where is a proof game witrh a pawn on b3?

I don't do proof games, I do logic (unless they pay me ). There is sufficient captured white material to explain the pawn positions. The only problem seems to be the capture of white's a-pawn. The little trick here is to first let black capture white's b-pawn with ..axb2, then promote white's a-pawn and finally sacrifice the promoted piece on e.g. b3.

Saved time: 55 minutes of entering boring proof game moves!

30 minutes

That's the advantage of youth!

Btw, you are supposed to deliver the proof game for the actual Blathy position (which starts with the white move: Kf2xNe1. They were sloppy in posting the one after move 1 as they thought it was illegal anyway!

^white could still promote the a pawn without capturing the knight, so it should still be legal. I didn't even consider promotion of the pawns to relocate them. I don't like the original blathy position since it is just a trivial capture. The real annoying thing is that there's no way to put the 2nd black knight in there without effecting the puzzle solution.

Right! But the new position is easier to retract (the a-pawn need not promote). To do justice to Blathy we should establish that this was not one of his illegal constructions!

I would assume the h pawn also has to be the only remaining white pawn for that position?

Can someone please try #5749?

@5763

So we need 2 proof games: one with Ne1 and Rb3 and one with Ne1 and Rc2.

Fun fact: chess.com would declare the game drawn for insufficient material once white plays the winning h8=N.

No, I don't think so. If the last white pawn is on another file then the white h-pawn can promote before being captured (just like the a-pawn). But white can't have 2 pawns on the board (when a black pawn is on b3).