open file

An open file in chess is a file with no pawns of either color on it. In the diagram, the e-file is an open file. An open file can provide a line of attack for a rook or queen. Having rook(s) and/or queen(s) on open files or half-open files is considered advantageous, as it allows a player to attack more easily, since a rook or queen can move down the file to penetrate the opponent's position.