Japan's top court on Wednesday again ruled legal provisions forcing married couples to use the same surname are constitutional, upholding a Supreme Court judgment from 2015.

The latest decision on a more than century-old provision based on the Civil Code and the family register law dismissed requests filed by three couples in 2018 to keep their separate surnames after local governments refused to accept their marriage registrations.

The decision handed down by Presiding Justice Naoto Otani at the Supreme Court's Grand Bench, composed of all 15 justices, came at a time when families have become more diverse, and public opinion on surname sharing has shifted in Japan.

The ruling said the top court has "found no points that should be changed from the decision in 2015, even as it takes into account the changes in the society and awareness among people," such as the increase in working women and more people in favor of allowing different surnames.

Among the 15 justices, four said prohibiting separate surnames was unconstitutional, compared with five who expressed the same view in the 2015 ruling.

Yuko Miyazaki and Katsuya Uga, two of the four justices, wrote in the ruling that it is an unjust "intervention by the state not to allow legal marriages unless couples accept the same surname, even if they do not wish to."

The latest decision again said the surname issue is a matter that should be discussed in parliament rather than seeking a judicial settlement.

Japan is the only country in the world known for having a law forcing married couples to share a surname, according to the Justice Ministry. The United Nations Committee for the Elimination of Discrimination against Women has also recommended that Japan change the system.

The three couples, all in common-law relationships, had appealed to the Supreme Court after the Tokyo Family Court and its Tachikawa branch dismissed their requests to legally marry while keeping their separate surnames in 2019. The Tokyo High Court turned down their appeals in 2020.

The couples, who asked not to be named, voiced disappointment and frustration after Wednesday's ruling.

"Some people think marriage is about sharing the same surname, but I hope they acknowledge a different value," a woman in the group said.

Another woman said at a press conference, "The ruling did not take individual rights into consideration properly," while her common-law husband said, "It is our generation's role to enable people to choose between the same or different surnames."

He also said the couple in their 40s is disadvantaged under the current system, which does not allow her to legally inherit his property.

Article 750 of the Civil Code stipulates "a husband and wife shall adopt the surname of the husband or wife in accordance with that which is decided at the time of marriage." The provision applies only to Japanese couples as foreigners married under the country's system are able to keep their family names.

One of the women involved in the case (2nd from L) speaks to reporters in Tokyo on June 23, 2021, after Japan's Supreme Court ruled again that legal provisions forcing married couples to use the same surname are constitutional. (Kyodo)

Critics say the provision originating from the 1898 Civil Code reflects the traditional concept of marriage as an arrangement involving families rather than individuals. Usually, a woman left her family to become part of her husband's family.

In 2019, 96 percent of couples who registered their marriage in Japan chose the husband's surname, according to government data.

The family register law stipulates a couple must determine a shared surname to have their marriage registration accepted.

The 2015 top court ruling said the practice of using the same surname was "well-established in society," and there is no gender inequality in the system.

But among 15 justices, the five, including all three women, said prohibiting separate surnames was unconstitutional, citing the disadvantages of changing a name.

The court acknowledged individuals who change their surnames, in most cases women, could "feel their identities lost" and face other disadvantages in terms of social credibility, but said people are not forbidden to go by their maiden names in the current system.

Many companies and public offices in Japan now allow female employees to retain their maiden names at work. The government has been slowly expanding the scope of official documents used for identification that show maiden names in addition to registered surnames.

Although the 2015 ruling called for discussions in parliament, they have not progressed much as members of the ruling Liberal Democratic Party are sharply divided over the issue.

Conservatives who seek to maintain traditional values are opposed to allowing couples to choose separate surnames, arguing the move may impact family unity and children. Both those against and in favor of the change have formed groups to push discussions further.

But the party's working group set up earlier this year to seek common ground last week gave up on drafting a specific proposal ahead of a House of Representatives election to be held later this year.

Jun Azumi, the Diet affairs chief of the main opposition Constitutional Democratic Party of Japan, called the top court decision "outdated" and told reporters his party will promise voters during the next lower house election to "respond to the matter in a manner fitting with the times."

In December, the government did not commit to allowing different surnames in its basic gender equality promotion policy following intense opposition by conservative LDP members.

Chief Cabinet Secretary Katsunobu Kato said at a press conference Wednesday the government will continue to study the issue, as stipulated in the promotion policy, based on the ruling and considering public opinion and discussions in parliament.

A Kyodo News survey conducted in March and April showed 60 percent of respondents in Japan said married couples should be able to have separate surnames, while 38 percent said they are against the idea.

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