Japan's Imperial Succession Crisis: Is Prince Hisahito the Last Emperor?

On Saturday, Japan's Imperial Palace filled with ceremony as Prince Hisahito, now 18, formally entered adulthood—a milestone that should have felt like continuity but instead underscored a looming crisis. Dressed first in a tuxedo, then in traditional beige robes, he received a ceremonial crown from Emperor Naruhito, bowed deeply in gratitude, and later changed into formal black attire to ride in a horse-drawn carriage to three sacred shrines. The rituals were elaborate and steeped in centuries of tradition. They were also a stark reminder that Hisahito may be the last male heir the world's oldest hereditary monarchy will ever produce.

The numbers tell the story plainly. Emperor Naruhito has one child: Princess Aiko, barred by law from succession. Crown Prince Akishino, the Emperor's brother and current heir, has one son: Hisahito. Beyond them sits Prince Hitachi, 89 years old, technically third in line but realistically too elderly to ever assume the throne. That is the entire pool of viable male successors to a monarchy that has endured for over 1,500 years. Hisahito, a freshman at Tsukuba University studying biology with a particular passion for dragonflies, now carries the weight of that entire lineage on his shoulders—a burden made heavier by the fact that no male heir exists after him.

This crisis is not accidental. It is the product of law. In 1889, Japan's prewar Constitution legally restricted imperial succession to males for the first time in the monarchy's history. The postwar 1947 Imperial House Law reinforced that restriction, cementing what had once been flexible. Historians note that the system worked in earlier centuries largely because concubines, who were part of the Imperial Court until roughly a century ago, ensured a steady supply of male heirs. That mechanism no longer exists. What remains is a rigid rule that bars women from the throne despite the fact that eight female empresses have ruled Japan—the last being Empress Gosakuramachi, who reigned from 1762 to 1770.

Princess Aiko, the Emperor's daughter, is highly popular among the Japanese public and has strong support as a potential future monarch. She is also legally ineligible. In 2005, the government proposed allowing female succession to safeguard the throne's future. The proposal gained traction until 2006, when Hisahito was born. Conservative factions and nationalist groups seized on his arrival as reason to abandon the reform effort. The momentum evaporated. In January 2022, a panel of conservative experts recommended a different path: maintain the male-line succession while allowing female royals to retain their status after marriage and continue official duties. They also suggested adopting male descendants from now-defunct branches of the Imperial Family to preserve the male lineage. These discussions stalled, particularly over whether non-royal husbands of princesses and their children should be granted royal status.

The weight of this impasse has become impossible to ignore. Shingo Haketa, former chief of the Imperial Household Agency, wrote in the Yomiuri newspaper earlier this year that Hisahito now bears the burden of the monarchy's survival almost alone. "The fundamental question is not whether to allow male or female succession line but how to save the monarchy," he stated. In May, the Yomiuri itself—a conservative publication—called for urgent reforms, urging lawmakers to amend the Imperial House Law to allow husbands and children of princesses to gain royal status and to permit women to inherit the throne. The editorial warned that parliament must "responsibly reach a conclusion on the crisis surrounding the state and the symbol of the unity of the people."

Hisahito himself seems aware of the expectations placed upon him. At his first official news conference in March, he expressed his academic ambitions, hoping to focus his studies on dragonflies and other urban insect species, exploring ways to protect their populations. He delayed his coming-of-age ceremonies by a year to prioritize his university entrance exams. Now, as a formal adult member of the Imperial Family, he will travel to Ise Grand Shrine, Japan's most sacred Shinto site, and visit the mausoleum of Emperor Jinmu, the mythical first emperor. He will also pay respects at the grave of his great-grandfather, wartime Emperor Hirohito. On Wednesday, he is scheduled to have lunch with Prime Minister Shigeru Ishiba and other dignitaries.

What happens next depends on decisions that have been deferred for nearly two decades. Japan's broader demographic crisis—a rapidly aging population and declining birth rates—mirrors the monarchy's own succession problem. The government faces a choice: reform a 135-year-old law that has no historical precedent in the monarchy's 1,500-year existence, or watch the throne face an unprecedented crisis. Hisahito's coming-of-age ceremony was meant to celebrate tradition. Instead, it exposed how fragile that tradition has become.