Three powerful Weapons in Endgame
The former world champion Emmanuel Lasker wrote: "There are three powerful weapons in endgame: Passer, King activity and Zugzwang!" In the following example we can see all three "weapons" at work
1. White king activity vs. Black passer
As we have seen White has missed to make the best of his King activity. He lost his bishop for the passer and the black king came out of "prison". Nevertheless White seemed to be near a draw cause of his active king, active rook and the advanced h-pawn. But remember what Lasker said: "... three powerful weapons in endgame ... and the Zugzwang".
2. Rook exchange and Zugzwang
So we have seen all three Lasker-"weapons" at work. White didn´t use his suberb King activity consequently enough, so Black was able to get some benefit by his Passer and finally the white king lost his activity and landed in "prison". Then a Zugzwang decided the game!