There was a case in which Imperial Prince Naruhito, the first grandson of the Emperor Showa, became an agent when Emperor Showa was treated medically and Crown Prince Akihito was traveling abroad.
国事行為臨時代行については、昭和天皇病気療養時に、皇太子明仁親王の外国旅行が重なり、皇長孫である徳仁親王が代行となった例がある。