TOKYO – Japan’s Prince Hisahito, the second-in-line to the country’s ancient Chrysanthemum Throne, has entered adulthood with his 20th birthday celebration on Sunday, arriving at a pivotal moment for the world’s oldest continuous hereditary monarchy as controversial new succession rules place the future of the 1,500-year-old institution firmly on his shoulders.
The nephew of reigning Emperor Naruhito, Hisahito is the youngest member of a rapidly shrinking and aging imperial household that counts just 16 living members today. Once a curious child with a deep fascination for wildlife and insects – particularly dragonflies – the new adult is now a second-year biology major at the University of Tsukuba, located just outside Tokyo. Campus onlookers regularly spot the prince navigating campus on his bicycle with friends, and he has even been seen carrying an insect-catching net between classes, leaning into his long-held love of the natural world.
While he has prioritized completing his academic studies to date, Hisahito has begun gradually taking on formal imperial obligations in recent months. In May, he joined a state banquet at the imperial palace for visiting Philippine President Ferdinand Marcos Jr., and in August, he traveled to Hiroshima to offer prayers to victims of the 1945 atomic bombing, before taking part in a youth camp hosted by the southwestern city.
Hisahito’s path to the throne has been shaped by a deeply unpopular legislative change passed by Japan’s national parliament in June: an update to the Imperial House Law that codifies male-only succession to the Chrysanthemum Throne, and has sparked widespread public backlash across the country. Under the revised rules, which amend a 19th-century original law, the ban on adopting male heirs from distant branches of the former imperial family has been lifted, while female royal family members are now permitted to retain their imperial status after marrying commoners – though their spouses and children will never be granted royal status, barring female lines from the line of succession.
This revision has drawn widespread condemnation as outmoded and discriminatory by critics, who point to broad public support for Princess Aiko, Emperor Naruhito’s 24-year-old daughter. Aiko, who is vastly popular with the Japanese public for her warm interpersonal skills and approachable demeanor, is barred from the succession entirely because of her gender. Polling consistently shows a majority of Japanese citizens support changing the law to allow her to succeed her father, but the revision, backed by conservative Prime Minister Sanae Takaichi, has instead cemented male-only succession, leading critics to argue it was crafted specifically to exclude Aiko from the throne and entrench patriarchal gender norms in Japan’s royal institution.
Crown Prince Akishino, Hisahito’s father and the first-in-line to the throne, has previously shared that he holds mixed feelings about the controversial new law. Academic and royal affairs experts warn that the new succession framework will place extraordinary pressure on Hisahito and his future wife: the entire future continuity of the imperial institution will depend on the couple producing a male heir, a burden that will shape their public and private lives for decades.
Speaking to reporters at his first major public press conference last year, Hisahito addressed questions about his future plans and potential marriage. At the time, he emphasized that his current priority is completing his studies, and shared his desire to travel abroad in the future to gain global perspectives and connect with people from diverse cultural backgrounds. “About marriage, I haven’t thought about an ideal timing or a partner yet,” he told reporters.