TOKYO - Japan is facing the longstanding issue of ensuring a stable imperial succession due to the shrinking size of the imperial family and is now seeking to reverse that trend.
An envisaged revision of the Imperial House Law would clear the way for the adoption into the imperial family of male members of former branches that were stripped of their status after World War II and enable female members to retain their imperial status after marriage to commoners.
The world's oldest hereditary monarchy has restricted succession to patrilineal descendants or those descended from an emperor on the father's side, a tradition that conservatives like Prime Minister Sanae Takaichi are determined to preserve.
Takaichi, the country's first female prime minister, has made it clear that the urgency to ensure a stable imperial family does not mean changing that tradition.
"The unparalleled historic fact that the imperial line has been maintained through the male line for 126 generations is the foundation for the emperor's authority and legitimacy," she told fellow ruling party members.
In a society deeply rooted in patriarchy, the proposed changes to expand the size of the imperial family from its current 16 members reflect such a preference, with little progress on paving the way for expanding succession to women, as Britain has done.
Currently, there are only three heirs to Emperor Naruhito, 66 -- his younger brother, Crown Prince Fumihito, 60, his nephew, Prince Hisahito, 19, and his uncle, Prince Hitachi, 90.
If the 1947 law is amended, male-line male descendants of former imperial branch families aged 15 or older and without a spouse or children could be adopted, according to the draft bill submitted to parliament on Tuesday.
Those adopted would not have imperial succession rights, but their descendants would. While Prince Hisahito is eligible for succession, if he does not have male children in the future, a male descendant of an adopted member could ascend the Chrysanthemum throne.
Tracing the male lines in the monarchy, 11 former branch families share a common ancestor with the current emperor, dating from around 600 years ago.
The declining size of the imperial family is due to a multitude of factors.
In 1947, 51 members of the 11 former imperial branches were excluded from the imperial family, reducing its size from 67 to 16. The number rose to 26 following the birth in 1994 of Princess Kako but currently stands at 16.
One reason for the decline is the difference in treatment of male and female members. When a male member marries, his spouse and their children become members of the imperial family.
But female members who marry commoners leave the imperial family, something that would change under the envisaged legal revision.
While the wishes of female members regarding retention of their imperial family status would be respected, their spouses and children would not become members.
A female member who retains her imperial status would remain in the genealogical register, while her spouse and children would be listed in a separate family register.
Those affected would be the emperor's daughter, Princess Aiko, 24, as well as the second daughter of Crown Prince Fumihito, Princess Kako, 31, Princess Akiko, 44, and Princess Yoko, 42, of the Mikasa branch, and Princess Tsuguko, 40, of the Takamado branch.
"They are supposed to remain after marriage to sustain the imperial family's activities, yet they would end up with a new status that is like something in between an imperial family member and an ordinary citizen," a senior Imperial Household Agency official said.
The proposed changes, approved by Takaichi's Cabinet, are based on discussions among the ruling and opposition parties. But opposition lawmakers have criticized the government for disregarding the "consensus" of the legislature.
The Centrist Reform Alliance had stressed the importance of family unity, taking issue with the fact that the spouse and child of a female imperial member would remain ordinary citizens.
But the proposed revision reflects the alarm among conservatives that Japan could open the way for an emperor from a female line.
Among the 126 monarchs in Japan's history, there have been eight women across 10 reigns, including Empress Suiko and Empress Jito, all of whom inherited the throne from their fathers.
Despite this, Emperor Naruhito's daughter Aiko is currently not eligible to succeed her father.
In Britain, monarchical succession was previously based on male-preference primogeniture, but a 2013 legal change shifted it to gender-equal primogeniture. Sweden and Norway have also changed from male-only succession to firstborn priority.
There were also discussions in Japan in the past about allowing female monarchs and emperors from the female line.
Takaichi appears to be taking a cautious stance, saying the time is "not ripe" for a debate on the period after Prince Hisahito's generation.
The public, however, appears more supportive of allowing a female monarch, with 83 percent of respondents in a Kyodo News survey in May in favor.
In order to ensure a sustainable imperial family system, the draft law states a review should be conducted every three decades if required.
"To enter the imperial family, (adoptees) would have to give up the careers they have built. Will someone with that resolve really come forward?" an employee attached to one imperial family branch added.
