Japan's parliament approved a bill on Friday to help the imperial family avoid running out of heirs. The bill lets the royal family adopt distant male relatives and allows women who marry outside the family to keep their royal status. But it does not change the rule that only men can become emperor (BBC).

Japan's royal family is the oldest continuous monarchy in the world, with a history stretching back more than 2,600 years. Right now, only three people are eligible to take the throne: Crown Prince Fumihito, 60, who is first in line; his 19-year-old son Prince Hisahito, who is second in line; and the emperor's 90-year-old uncle, who is the last eligible candidate. If Prince Hisahito does not have a male child, the line of succession could end (BBC).

The rules for who can become emperor are set by a law called the Imperial House Law. This law says that only men who are descended through the father's side can inherit the throne. The law also says that the imperial family may not adopt children (Imperial Household Agency). The new bill creates a narrow exception to that ban.

Under the new bill, male descendants of 11 former royal branches can be adopted back into the imperial family if they are over 15. These branches lost their royal status after World War II, when the American-led occupation of Japan reduced the size and political power of the imperial household. The idea of bringing these descendants back has been discussed in Japanese policy circles for years as a way to expand the shrinking pool of eligible men (BBC).

The second part of the bill lets female members of the imperial family keep their royal status after marrying outside the family. Under the old rules, women who married commoners lost their royal status and had to leave the household. Keeping their status would not give them or their children the right to inherit the throne, but it would slow the shrinking of the imperial family (BBC).

Princess Aiko, the only child of the current emperor, remains ineligible to take the throne under the new bill. Polling cited in the reporting shows wide public support in Japan for a female emperor, but the legislation keeps the prohibition in place (BBC).

The question of whether a woman could become emperor has been discussed for over a decade. In a 2022 press conference, Emperor Naruhito referenced a government advisory panel report that had offered two proposals for securing enough imperial family members (Imperial Household Agency). Japan's own Imperial Household Agency has pointed to international examples: it noted that Denmark revised its succession law in the 1950s to allow a female sovereign, which led to Queen Margrethe II taking the throne (Imperial Household Agency).

The path to this bill has been deliberate. Prime Minister Takaichi Sanae gave a policy speech on October 24, 2025, that referenced a revision of the Imperial Household Law regarding succession (Prime Minister's Office). That speech signaled the government's plan to act on the succession question, and the bill's passage through both houses of parliament in July 2026 is the result.

The broader backdrop includes Japan's most recent imperial transition. In December 2017, the Imperial House Council decided that a special law should take effect on April 30, 2019, allowing Emperor Akihito to step down — something no living emperor had done in over two centuries — and letting Emperor Naruhito take the throne (Prime Minister's Office). That rare event sharpened the debate over the dynasty's future.

The adoption part of the bill is the more novel change. Adoption within the imperial family was practiced in earlier eras of Japanese history, but Article 9 of the current Imperial House Law closed that door entirely. Reopening it, even for just the 11 former branch descendants, reverses a legal boundary that has stood for nearly eight decades. The provision does not immediately add anyone to the line of succession; it creates a way to bring eligible men in if the need arises.

The rule letting women keep their royal status after marriage is also forward-looking. It does not restore status to women who already left, and it does not change the succession rules for their children. Its practical effect is to keep the imperial household larger as members age and the pool of eligible men stays small.

What the bill does not do is address the biggest question: whether women should be allowed to become emperor. Princess Aiko is the only child of the reigning emperor, and public support for a female sovereign is strong according to available polling. The legislation's architects chose to expand the pool of eligible men rather than open the throne to women, a decision that goes against majority public opinion and preserves the male-only succession rule at the heart of the system. Whether that rule can last without further reform depends, as things stand, on Prince Hisahito.