Try this!
Rook and Pawn endings are simple positions that are at times just diabolical in their complexity. This one is a beauty. See what you can do with this one.
Okay. Here it is. From this position, Black to move, you have what I call a node. This one is quite intense because it goes on for four moves. What I mean is this. For four moves, Black has one and only one move that wins. Can you do this?