Photo/Illutration Lawmakers of the ruling Liberal Democratic Party on Dec. 4 discuss guidelines to ensure gender equality. The issue of dual surnames was raised at the meeting. (Sawa Okabayashi)

Lawsuits filed over the constitutionality of a legal provision that prevents married couples from registering separate surnames are heading to the Supreme Court’s Grand Bench.

The top court’s Petty Bench on Dec. 9 decided to refer three cases, filed by couples in de facto marriages, to the Grand Bench.

The Grand Bench in December 2015 upheld the constitutionality of a long-standing Civil Code stipulation that requires married couples to use the same surname.

But this time, the issue is also about whether the Census Registration Law, which requires married couples to register under the same surname, violates the constitutional guarantee of equality.

Chief Justice Naoto Otani and 14 justices will hear the case. The time schedule and other details have yet to be decided.

The three couples who live in Tokyo filed a petition for Adjudication of Domestic Relations at the Tokyo Family Court and its Tachikawa Branch.

They had tried to register their marriages in the cities of Kokubunji and Hachioji, as well as in Setagaya Ward, from February to March in 2018.

The couples were each asked to select one surname, but they checked the boxes for both of their names instead. Their marriage registrations were denied.

The three couples demanded that the city and ward mayors accept their marriage papers, arguing that laws that recognize marriages of couples with one surname but deny that status to couples who want separate surnames “violate the Constitution that guarantees equality under the law.”

The Tokyo Family Court and its Tachikawa Branch cited the 2015 Supreme Court ruling in dismissing the complaints, saying, “Choosing one surname for a family has taken rooted in society and is reasonable.”

The rulings also said many married couples choose the husband’s surname in reality, and that “is not discrimination born out of the Civic Code.”

The Tokyo High Court later rejected the couples’ appeals.

The couples then each filed a special appeal, arguing that “social circumstances have changed since the 2015 Supreme Court decision.”

They cited the fact that by July 2020, 102 local assemblies had released opinion papers and other documents calling for the introduction or discussion of a system that allows married couples to have different surnames.

The Justice Ministry’s Legislative Council in 1996 submitted a report to the justice minister that included a plan to reform the Civic Code to allow married couples to have separate surnames.

But no legal amendments have been made on the issue, mainly because of opposition from conservative elements in the ruling Liberal Democratic Party.

The Cabinet Office in 2018 released a public opinion survey that showed a record high 42.5 percent of respondents believed it would be good to allow married couples to have different surnames. That ratio far exceeded the 29.3 percent who said such a change was unnecessary.