Japan is facing growing calls to reconsider its male-only imperial succession rules as concerns mount over the shrinking royal family and the future of the Chrysanthemum throne.
Princess Aiko, the 24-year-old only child of Emperor Naruhito and Empress Masako, has emerged as a central figure in the debate, with a majority of Japanese citizens supporting the possibility of a woman becoming emperor. Despite her popularity and growing public profile, Aiko remains ineligible to succeed her father under the country’s existing succession laws.
The issue has reignited discussions about whether a centuries-old tradition should be retained amid changing public attitudes and a declining number of eligible male heirs. A survey conducted by Japanese newspaper Mainichi Shimbun in April found that 72% of respondents supported the idea of a woman ascending the throne, while 10% opposed it.
The findings underline the gap between public opinion and the position maintained by conservative political leaders on the issue. Japan’s imperial household has witnessed a significant decline in its membership over the past three decades.
From around 30 members previously, the family now has only 16, including five men. Of these, just three are eligible under the current rules to succeed to the throne: Emperor Naruhito’s younger brother, Crown Prince Akishino; Akishino’s son, Prince Hisahito; and the emperor’s 90-year-old uncle, Prince Hitachi. Prince Hisahito, who is studying at university, is particularly important to the future of the imperial lineage. If he does not have a son, the existing male line of succession could face a serious crisis within a generation.
The shortage of eligible heirs has increased pressure on the government to find a sustainable solution. The current restrictions are rooted in legislation introduced during the Meiji era in 1889 and retained in the Imperial House Law enacted in 1947. The rules prohibit women from ascending the throne and require succession through the male line.
Although previous governments considered reforms that would permit female succession, opposition from conservative lawmakers and the birth of Prince Hisahito in 2006 brought the debate to a halt. The government of Prime Minister Sanae Takaichi, Japan’s first woman to hold the office, has continued to support the existing male-only succession system.
Amendments passed this year aim to address the shortage of imperial family members without allowing women to become emperor. Under the changes, female members of the imperial family will be permitted to retain their royal status after marrying commoners. The legislation also provides for the possible adoption of unmarried male descendants from former branches of the imperial family that lost their royal status after the Second World War. Their sons could become eligible for succession under the revised arrangements.
However, the measures have drawn criticism from those who believe they fail to address the underlying problem. Makoto Okawa, a professor specialising in imperial lineage and succession at Chuo University in Tokyo, said the changes clearly indicated a continued commitment to maintaining succession through the male line.
Takaichi has defended the approach, arguing that the reforms are intended to stabilise the imperial household rather than reopen the question of female emperors. During parliamentary discussions, she stressed the historical continuity of the male line, describing it as fundamental to the emperor’s authority and legitimacy. The debate has also attracted international attention.
In 2024, the United Nations women’s rights committee urged Japan to reconsider its restrictions on female succession. The Japanese government rejected the intervention, maintaining that the imperial succession was closely connected to the country’s national identity. Meanwhile, Aiko’s growing popularity has strengthened calls for change.
Her public appearances and official engagements have earned her considerable admiration, with supporters pointing to her composure and ability to connect with people as reasons she should be considered for the throne. An admirer who runs an Instagram account dedicated to the princess said the government was disregarding widespread public support for revising the succession rules.
Supporters argue that Aiko, as the emperor’s only child, should not be excluded from consideration solely because she is a woman. Japan has had eight female monarchs in its history, although their reigns were generally viewed as a means of maintaining the imperial line until a male heir could succeed.
The most recent was Empress Go-Sakuramachi, who ruled from 1762 to 1770. Members of the imperial family are prohibited from commenting directly on political matters, but recent remarks by senior royals have added to the discussion. Emperor Naruhito said in June that he hoped parliamentary deliberations on securing the future number of imperial family members would gain public understanding.
Crown Prince Akishino also emphasised the need for society to progress, stating that the imperial family should respond to the expectations of society and that he did not believe there were differences between men and women in this regard. Whether these sentiments translate into changes to the law remains uncertain.
With public support for female succession growing and the pool of eligible male heirs continuing to narrow, Japan faces an increasingly pressing question about how to preserve its imperial institution while responding to changing social attitudes.
