TOKYO—Concerns over the long-term sustainability of Japan's imperial family have intensified after parliament approved the first substantive revision of the Imperial House Law since 1947, retaining the country's male-only succession system while adopting measures intended to address the monarchy's shrinking membership.
The legislation, enacted on July 17, allows female members of the imperial family to retain their imperial status after marrying commoners and permits the adoption of male descendants from former imperial branches that lost royal status after World War II. The revised law, however, preserves the principle that only men in the paternal line may inherit the Chrysanthemum Throne, leaving Princess Aiko, the only child of Emperor Naruhito, ineligible to succeed.
The government has said the changes are designed to ensure the imperial household has enough members to carry out official duties while maintaining what it describes as the historical basis of imperial succession. Supporters of the legislation argue that expanding the number of family members through adoption and allowing princesses to remain in the household after marriage will help sustain the institution without altering the succession principle.
The succession issue has drawn renewed attention because the imperial family has only a small number of male heirs. Under the current order of succession, Crown Prince Fumihito, his son Prince Hisahito and Prince Hitachi are among the remaining eligible male members. Demographic pressures have raised concerns about the family's long-term continuity.
Former Imperial Household Agency Grand Steward Shingo Haketa said discussions on securing stable succession should continue despite the legislative changes. In comments published before the bill's passage, Haketa said the revisions addressed the shortage of working royal family members but did not fully resolve questions surrounding long-term succession, urging policymakers to seek a solution capable of gaining broad public understanding.
The legislation has also prompted criticism from some academics, opposition lawmakers and commentators, who argue that maintaining male-only succession excludes potential female heirs despite opinion polls in recent years indicating substantial public support for allowing a woman to ascend the throne. The government has maintained that preserving the male-line succession system remains essential to the legitimacy of the imperial institution.
With the revised law now enacted, attention is expected to shift to its implementation and to any future parliamentary discussions on longer-term succession arrangements, although no further legislative changes have been officially announced.
