Rook in front of 7th rank pawn
Rule 1: The rooks place is behind a passed pawn (your own or the oponents).
Here the black rook is blocking the pawn, but the king cannot reach there. All white has to do is to bring in the king. 3. Kd4 Kg7 4. Kc5 Kf7 5. Kb6 +-
This was a basic win for white. The situation is different if black has the rook behind the passed pawn. Then it could be a draw:
Rule 2: In these positions, whenever the King touches the pawn (trying to free its Rook), the defender should smack it away immediately with a check
1. Kc5 Ra2 Keeping the rook behind the passed pawn keeps the white rook locked at least until the king arrives. Other moves like Kg7 and Rc1+ are also OK, but carrying the checks too far is a mistake. Checking at Ra5+ is also loses the draw. See below. Here is the main plan:
2. Kb6 Rb2+
Rule: In these positions, whenever the King touches the pawn (trying to free its Rook), the defender should smack it away immediately with a check
3. Kc7 Ra2 Remember: The defending rook should always stay behind the pawn, failing to do so frees up the white rook.
4. Kb7 Rb2+ 5. Kc6 Ra2 Here white should shake hands and accept draw. [1/2-1/2]
How about the checks at Rc1+ og Ra5+? Why do they lose?
See the game for all the variations
(Notes from Silmans' complete endgame course)