Princess Aiko (right) and Princess Nobuko attend the New Year's general public greeting ceremony at the Imperial Palace in Tokyo on Jan. 2. [AFP]
Princess Aiko (right) and Princess Nobuko attend the New Year's general public greeting ceremony at the Imperial Palace in Tokyo on Jan. 2. [AFP]

Japan's political establishment has drawn criticism at home and abroad for amending the Imperial Household Law to extend succession rights to male-line descendants as distant as 36th cousins — while bypassing any discussion of allowing women to ascend the throne.

Japan's upper house passed the revised Imperial Household Law on Friday, clearing the way for male-line descendants of former imperial families to be adopted into the royal household. Under the amendment, any son born to such an adoptee would be eligible to succeed to the throne.

The amendment specifies that the adoptee himself would not hold succession rights, but any male child born to him would.

It marks the first time the main provisions — rather than supplementary clauses — of the Imperial Household Law have been revised since 1949.

The former imperial family members eligible for adoption share a common ancestor with Emperor Naruhito dating back roughly 600 years, placing them 36 to 38 degrees of kinship removed from the current emperor.

Princess Aiko, Emperor Naruhito's only child, cannot succeed to the throne under the law's male-line-only rule.

Japan's political class ultimately expanded the options for male succession without ever putting female succession on the table.

UN Secretary-General Antonio Guterres said Friday, in response to a media question about the revision, that he "encourages inclusive policies that lead to the advancement of women's rights in all positions and professions in all countries," according to Japan's Jiji Press.

The remark was widely interpreted as an indirect rebuke of the amendment's effective exclusion of women from succession.

Earlier, the UN Committee on the Elimination of Discrimination against Women recommended in 2024 that Japan revise the Imperial Household Law, saying its male-only succession rule was incompatible with the principles of the Convention on the Elimination of All Forms of Discrimination against Women.

The Japanese government at the time pushed back, arguing that eligibility to ascend the throne is not a fundamental human right and therefore does not constitute gender discrimination.

Major Japanese outlets including the Yomiuri Shimbun gave prominent coverage to the passage of the first substantive revision to the Imperial Household Law since 1949, criticizing it as out of step with public sentiment.

In an editorial headlined "A blow to the foundations of the symbolic imperial system," the Yomiuri said the revision was "a reckless institutional change, riddled with too many flaws, that ignores the bond between the people and the symbolic emperor that has grown over 80 years since the war."

The Asahi Shimbun cited Emperor Naruhito's recent remark that he hoped "discussions would take place that earn the understanding of the people," and said politicians had ignored the fact that 70 percent of the public supports allowing women to succeed to the throne.

Japanese media also noted that while other monarchies — including those of Spain, the Netherlands and Sweden — have adopted gender-neutral primogeniture, Japan alone continues to insist on male-line male succession, a principle they said is out of step with the times.

The conservative Sankei Shimbun, by contrast, defended the revision, noting that fewer than 10 percent of lawmakers voted against it.

The former imperial family members who could be adopted into the royal household share a common ancestor with Emperor Naruhito from roughly 600 years ago, making them 36 to 38 degrees removed. About six individuals are believed to meet the criteria under the revised law.


soohan@heraldcorp.com