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What is your favorite endgame position

An interesting position was just posted. Luxcat could turn it into an interesting problem by giving a stipulation.

Obviously white starts and wins
Oh my #368 puzzle was cool It was tricky and took me a while I will admit though. I don't want to give away spoilers to this puzzle yet; I don't want to ruin it for others so fast. I think I partially got lucky, but I think I only found it because I coincidentally have recently been studying Knight + pawn v. Knight endings.
Just curious where this puzzle came from though. Did you just invent it, or is it a famous endgame study that I hadn't previously seen?

It is a 1938 study by Vitaly Halberstadt.

To the best of my knowledge, it is a 2019 study by R. Amburgy.

Here is the key move in white text: Nxg6 . It seems the game could go on for at least 30 more moves, but White should have a decisive advantage after about eight more moves.

You're a little off there. Black can't play 2...f3+ because Black already played 1...f3+. What I said is, after 2. Kf1, Black would do better with Re2 than with Rxe1+.
interesing