In a historic move, Japan’s legislative body has cemented the tradition of male-only succession to the imperial throne, a practice rooted some 1,500 years in history.
This decision was formalized on Friday with a vote to amend the Imperial House Law from the 1800s, despite cautions from scholars that restricting heirship to exclusively male descendants could accelerate the demise of Japan’s already waning and greying imperial lineage, as reported by the Associated Press.
In response to the decreasing pool of potential future emperors, the updated law permits the adoption of distant male relatives into royalty to ensure a line of male successors. Nevertheless, the stringent rule that heirs must possess royal lineage persists. Additionally, these amendments will allow princesses who marry commoners to maintain their royal status.
Parliament’s decision has sparked discussions as a significant portion of the Japanese populace advocated for Princess Aiko, the 24-year-old daughter of Emperor Naruhito, to ascend the throne — a notion now rendered unachievable.
On April 10, 2024, Japan’s Princess Aiko, alongside Emperor Naruhito and Empress Masako, attended a ceremony commemorating the 110th anniversary of Empress Meiji’s death at Tokyo’s Meiji Shrine. (Kazuhiro Nogi/Pool Photo via AP)
“The emperor is a symbolic figure, and I don’t see why women cannot serve in the role,” Junichiro Tsujimaru, a 78-year-old sushi chain founder, told the AP.
Under current law, the 66-year-old emperor’s younger brother is next in line. After that, his 19-year-old nephew, Prince Hisahito, will inherit the throne, and then the emperor’s 90-year-old uncle.
Hisahito is the only boy to be born in four decades, and only five of the 16 adults in the imperial family are men.
Prime Minister Sanae Takaichi and other conservatives say the male bloodline is the source of the emperor’s authority and legitimacy.
Japan’s Prime Minister Sanae Takaichi speaks during a news conference at the prime minister’s office in Tokyo, Oct. 21, 2025. (Eugene Hoshiko)
“It’s a declaration to prevent female monarchs … and to defend the male-lineage at all costs,” Hideya Kawanishi, a Nagoya University expert on monarchy, told the AP. “They cannot say it’s male chauvinism, so they call it tradition.”
Chizuko Ueno, a prominent feminist and sociologist, recently suggested it was ironic that Japan’s first female prime minister was the one to ensure male-only succession.
Ueno said the new rules “treat male royals as stallions and put female royals under pressure as ‘childbearing machines’ to produce male offspring.”
Japan has had eight empresses descended from the male line in its centuries-long history as a hereditary monarchy. The last woman to reign was Empress Go-Sakuramachi, who sat on the throne from 1762 until 1771, when she abdicated in favor of her nephew.
Japan’s Prince Hisahito, right, attends his coming-of-age rituals on his 19th birthday at the Imperial Palace in Tokyo, on Sept. 6, 2025. (Japan Pool/Kyodo News via AP)
Female eligibility for the throne was first eliminated in 1890 under the original Imperial House Law.
That change was carried over into the modern Imperial House Law, enacted in 1947, the same year Japan’s new constitution stripped the emperor of governing authority after the country’s defeat in World War II.
Like Britain’s royal family, Japan’s imperial family remains an important national symbol.