King vs king & rook-pawn position?

@Sipo #9 Pawn endings can be very tricky, so I try to calculate, unless the position is very clearly drawn or won. See old blog post of mine about tricky pawn endings : https://www.chess.com/blog/achja/those-tricky-pawn-endings Even top GMs can go wrong in pawn endings, see e.g. here (This was a game I watched "live" via Internet, hence it was easier to remember this one) : http://www.chessgames.com/perl/chessgame?gid=1782562 This pawn ending is actually not so easy at all. Even the chess engines need more time to see that white is winning. https://lichess.org/c1v057T9#85