The first rule of Passed Pawns
Many an endgame is decided by which player is able to promote a pawn. So, it is very important to know how to handle a passed pawn. Starting with the definition: a passed pawn is one which cannot be stopped by any enemy pawn. That means there isn’t one in front of it, nor on the file left or right which could ever capture it.
Obviously, passed pawns must be pushed. And the best way to help with that is to put a rook behind a passed pawn.
From behind, the rook will support the pawn’s advance, protecting it no matter how far it moves. And, unlike being in front of the pawn, the rook will never need to move out of the pawn’s way, which can sometimes be very awkward to do. On the flip side, it is wise to put something in front of a passed pawn to block it, for example …Rc6 in the above position.
Actually, putting a rook behind a passed pawn is a great idea if it’s your opponent’s pawn too. For similar reasons, the rook will do a great job slowing down its advance and keeping it under control. Try it out the next time you play.