Prince Hisahito, the nephew of Emperor Naruhito and second-in-line to the Chrysanthemum Throne, celebrated his 18th birthday on Friday. This makes him the first male member of Japan’s imperial family to reach adulthood in almost four decades since his father. Prince Hisahito is the only son of Crown Prince Fumihito and Crown Princess Kiko. He joins a small group of adult members in the imperial family due to restrictions outlined in the 1947 Imperial House Law.
In a statement released by the Imperial Household Agency, Prince Hisahito expressed his desire to learn and grow through various experiences. He also thanked those who have supported him over the years, including his parents and elder sisters. The prince intends to cherish his remaining time at high school.
Traditionally, a Coming-of-Age Ceremony and press conference would be held to commemorate this milestone. However, Prince Hisahito’s ceremony will take place in spring 2025 or later after he graduates from high school so as not to disrupt his studies.
Prince Hisahito is also notable for being the first imperial family member to reach adulthood under Japan’s revised Civil Code, which lowered the age of adulthood from 20 to 18 in April 2022. Princess Aiko, Emperor Naruhito’s only child, celebrated her coming-of-age when she turned 20 in 2021.
Apart from Prince Hisahito and Crown Prince Fumihito, there is only one other heir to the Chrysanthemum Throne: Emperor Naruhito’s childless uncle, Prince Hitachi.
The agency revealed that Prince Hisahito has a keen interest in natural history with a particular focus on insects’ habitats. He has actively engaged in fieldwork activities such as attending expert lectures and reading related materials. Last year, he coauthored an academic paper on dragonflies that was published by Bulletin of National Museum of Nature and Science.
While attending school, Prince Hisahito has gradually started participating in royal duties alongside his studies. For instance, he accompanied his father during their visit to Gifu Prefecture for two days at a national culture festival for high schools last July.
With several female members marrying outside of royalty—including Princess Mako—there are currently only seventeen royal members carrying out official duties within Japan’s imperial family; twelve are women including Princess Aiko and Princess Kako (the prince’s sister).
The issue surrounding male succession rules within Japan’s imperial family has been subject to debate over recent years but lost momentum when Prince Hisahito was born as it provided an heir through direct male lineage after nearly four decades without one.