What is Building A Bridge?

Building a Bridge refers to a specific tactic in the endgame of a chess match. It involves the process in which a rook is used to prevent friendly king's exposure to checks in a pawn endgame. The term particularly comes up in a king and rook versus king and pawn scenario, where the stronger side's king needs to cross over a file that the opponent's king is guarding. The rook is used to 'construct a bridge' by being placed in between to allow the friendly king to pass and eventually promote the pawn to a queen.