Tokura describes the evidence found at the cottage to reporters and they ask if the neighbors will give away his proposed deception of the kidnappers, he states "It's a new development with few houses." But, when the boy, his father, and the two detectives are looking around the yard there is visible aging of the paint on the fence, siding, and window casings indicating that the house has not been painted in a few years.
When the police is reviewing the footage from the train (where the kidnappers retrieve the briefcase), the camera rotates 180 degrees backwards and, despite it having been recorded from the cabin, the view is never blocked.
The story goes in midsummer in Japan. This implies that Mt. Fuji has no snow. Since the location filming was carried out in winter season, the top of Mt. Fuji is very white. Some film critics mention that this is almost the only mistake they can find in the film.