Moving a rook off the bank rank, and up a few squares, in order to slide it to a new file so it can help in the attack without being blocked by its own pawns.

A maneuver that places a rook in front of its own pawns, often on the third or fourth rank. This can allow the rook to treat a half-open file as if it were an open file, or a closed file as if it were half-open.