would I have seen it?
Cool puzzle! One of the best I've seen in a while.
Pues, sí que lo vi
Am I mistaken to think this is a famous reti endgame study? At the very least it's a variation on its idea, that the king can attack and defend at once from opposite sides of the board in a king and pawn endgame under favorable conditions.
Easy enough, but still amazing in execution. It's hard to believe that useless king in the corner is the most dominant piece on the board...
this is a style of puzzle of which I forget the name but it's mentioned on Wikipedia