180-degree rule is a continuity convention keeping the camera on one side of an imaginary axis between two subjects so screen direction stays consistent.
The 180-degree rule is the foundation of spatial continuity in narrative film. An imaginary line — the axis of action — is drawn between the two main subjects in a scene; the camera must stay on one side of it. As long as it does, characters keep their consistent screen positions: if Person A is on the left and Person B on the right, they will remain so across cuts. Cross the line and the two appear to swap sides, which most viewers experience as disorienting even if they cannot name why. Yasujirō Ozu deliberately violated the rule throughout his career to create a meditative spatial flatness. Stanley Kubrick crossed the line in 'The Shining' (1980) to plant unease beneath domestic scenes. Wes Anderson breaks it constantly in service of his head-on, dollhouse compositions. Knowing the rule lets a filmmaker use it; knowing when to break it is what separates style from accident.