An Instructive Rook Endgame

The following rook endgame, and the way the players handled it, is very interesting. First it shows that even the best players often fail to grasp the subtleties of rook endgames; second, it is a good example with a very important idea to have in mind.

I must say that I first saw this position discussed in GM Alexander Khalifman's Facebook feed, so cred…