Prince Hisahito, Japan’s future emperor, has turned 20, reinforcing his position as the country’s second in line to the Chrysanthemum Throne after his father, Crown Prince Akishino.
The birthday comes under Japan’s male-only succession rules, which exclude Emperor Naruhito’s daughter, Princess Aiko, from inheriting the throne despite her place within the imperial family.
Prince Hisahito is studying biological sciences at the University of Tsukuba, near Tokyo, where he has developed a particular interest in insects, including dragonflies, as well as agriculture and the habitats of living creatures.
The Imperial Household Agency said he had spent the past year balancing his university studies with an expanding programme of official engagements.
Since his coming-of-age ceremony in September 2025, he has attended events at the Imperial Palace, including New Year ceremonies and a banquet held during Philippine President Ferdinand Marcos Jr’s state visit to Japan.
He has also taken part in public duties across the country, including visits to Hokkaido, Mie, Kyoto, Osaka, Nara and Hiroshima. In August, he attended a national scout gathering in Hiroshima, where he joined activities including tent-building, cooking and disaster-preparedness exercises.
Hisahito was born on September 6 2006 and became an adult member of the imperial family at 18, following a change to Japan’s civil law that lowered the age of adulthood from 20 to 18.
The line of succession remains a closely watched issue in Japan because the Imperial House Law permits only male members of the male line to become emperor. Hisahito is currently the only young male member of the imperial family in the direct line of succession.
