Not to be confused with some recent horror movies that share the same title (and boy do they look awful), Yoshitaro Nomura's 1970 film The Shadow Within is a thriller that relies on well-developed suspense rather than any cheap jump-scares, and the director truly earns the spectacular reveal at the end. Working with his frequent collaborator, crime novelist Seicho Matsumoto, Nomura expertly draws the viewer into the tale of a married man who falls into an affair with a single mother only to become convinced her young son is out to murder him. Our first glimpse of the boy is an evocatively backlit shot that obscures his features, and his motives become only more shadowy to the protagonist as the film gradually progresses from drama into something more sinister. A therapist would have a field day.