Theatre and film knots keep the rigging behind a show safe and quick to change between scenes. The essential stage rigging knots hold under load and untie fast. Known to riggers as the High Tie, the Backhand Hitch fastens a line to a pipe or batten and provides control during release while under strain. The Bowline, a rigger's favorite, puts a fixed loop on a line used to fly scenery or a lighting bar up to the grid. On a fly system, a Cleat Hitch ties the operating line off to a cleat or belaying pin at the rail until a cue calls for it to move. When a set piece or lamp has to be pulled in tight, the Trucker's Hitch gives a grip or stagehand the leverage of a block and tackle. The top theatre and film knots listed below cover the skills behind safe stage rigging. Because a rigged load hangs over people below, every knot is tied, backed up, and checked before the house opens.