Shortest-proof-game challenge

Proof game in 32.5.

Actually that position makes the game inevitably end after white moves, as white has no choice but to checkmate black last move, so it essentially is a game that ends in a half move.

Actually, a proof game ends when the target position has been reached.

12.0

This was quite a fun and unique prompt!

Thank you! I gotta admit, I didn't think anyone would find such a short game.

And there was a fool's mate as well! One day people will only make proof games with the reflex condition. Must give mate in 1. Then you'll have to navigate to avoid that obligation as well!

Actually, one such game does exist.

Nicolas Dupont, Julia's Fairies 12/3/2017

PG n 17.0, Black Reflexmate, meaning Black must checkmate if they can

Great to see! My prediction is from somewhere near 2010. It is an immensely rich terrain once you seriously start exploring it. I won a first prize with an A.P. logical retro-problem and reflexmate but not a proofgame!

^who would choose such piece graphics?!?!?!

I kept mistaking the bishops for knights

Yes, it's ugly, but it's an improvement over Rewan's previous style, which made the two sides' pieces hard to tell apart.

What's that mean exactly? It looks like it's White's move and after Ka8 Black can simply play Kf7.

Here's an example of what that condition means. If BishopTakesH7's challenge (#5701) had included the White Reflexmate condition, Leither123's neat solution (#5712) would be invalid because on move 3, White could mate in one with Qh5 and instead played Bc4.

Could Leither's proof game be fixed up so that the opportunity for White to mate in one never comes up?

Ah, so there must never be an opportunity to mate in one throughout an entire game?

Yes, unless the chance to mate in one comes on the final move of the proof game. And yes, Leither's solution can easily be changed to avoid the mate in one possibility.

While certainly not difficult, creating a solution with the reflexmate condition was trickier than it had initially seemed; I had to employ a slightly different strategy. The light squared bishop must make it onto g8 before the f-pawn promotes, but that opens up the queen and allows Qh5#. Ra5 was used to prevent this.

I challenge someone to find an alternative method, in which case I stand corrected.

Edit: I stand corrected. Ra5 is not a good move.

uhh am i missing something or 12. Be6#?

The final move can have a mate in one, just not the rest of the game.

Its not the final move though