Rook on long side, king on short side?

I stumbled upon this interesting position. Black to play. Only one move save the draw. Can you find it?

Wow.

If I had my Silman endgame book with me, I could answer it.

Is from the Philidor Gone Bad chapter.

I do not remember the exact line. See if I can take a crack at it. (Without tablebase.)

I think it was Kf8 here?

I think I failed here.

Checking tablebase now.

Yep.

I totally went the wrong way.

Nice puzzle!

The original position in #1 really confused me, since "King to the short side, rook to the long side!" was engraved in my heart. In fact, if the white rook was on a3 instead of b3 in the original position, both the long side and short side lose. As Gothral pointed out, it is only the lucky tempo that Black gains after 1...Kd8 2.Rb8+ Kc7 that give Black time to put his rook on e8--where it belonged in the first place.

If Black's rook was on e8, instead d8 in the original diagram, long side and short side both draw

Yep, that's also what confused me when I found this position 2 years ago since it seems to go against the rule of thumb. But I have to say excellent breakdown @Gothral! It's great how you explain it in terms of K&H defence and long side defence - gave me a better understanding.

I really have t learn to look at the dates on these posts! I had no idea I was responding to a pre-pandemic post.

Exactly! It turns out the actual position of the pieces is important! Who knew? But seriously, Black has clearly blundered on his previous move. which must have been Rd1+. If possible, he could have played his rook to the 6th rank, setting up an unbreakable Philidor defense. Or, if that was impossible, Re1 would also draw

Nice study.  Thanks for giving the helpful breakdown.

Good point, though I guess it's possible this stage of the endgame could have only just begun, following an exchange on e6 or b3.

Kd8 is the only move that draws according to Lomonosov TB.