The Tokyo District Court on Wednesday rejected a damages suit filed against the state by five people who claim a Civil Code article that forces married couples to choose a single surname contravenes the Constitution.

In the first suit to contest the constitutionality of the Civil Code’s Article 750, which was enacted in 1947, presiding Judge Masako Ishiguri turned down a claim of damages worth some ¥6 million in total by the five, aged 36 to 77, saying the Constitution “does not guarantee the right to use separate surnames.”

Article 750 says a husband and wife shall adopt the surname of either at the time of marriage.

The five — a common-law couple and three wives who go by their maiden name in daily life — claim the article violates Articles 13 and 24 of the Constitution, which stipulate respect for the individual and equality between husband and wife, respectively.

The plaintiffs argued the system forcing married couples to choose a single surname is “based on an old social convention” and “effectively causes gender inequality” as most Japanese women opt for their husbands’ name after marriage.

Wives changed their surname in about 96 percent of all marriages registered in 2011, according to the Health, Labor and Welfare Ministry.

The plaintiffs had complained of mental anguish over the Diet’s failure to revise the Civil Code.

The central government, meanwhile, had said the law pays due heed to respect for the individual and gender equality as husband and wife are equal in choosing the single surname.

But Ishiguri admitted that many couples have called for the option of using dual surnames after marriage due to the disadvantages that can be caused by changing a maiden name in both personal relationships and careers.

“A person’s name symbolizes his or her character and is part of a personal right, but the Constitution does not guarantee the right for a married couple to continue to use (separate) names,” the presiding judge said.

Lawmakers “were not obliged to enact legislation” to change the status quo, she found.

Plaintiff Kyoko Tsukamoto, 77, a former high school teacher, later told reporters: “Why do we have to change our important surnames after getting married? I want the system to be changed to allow the use of separate surnames.”

Plaintiff, Emi Kayama, 41, a freelance writer, indicated she will appeal the ruling, saying: “I believe the true nature of marriage has nothing to do with using a single surname. (Our battle) is not over yet.”

Calls for the system to be changed grew in the late 1980s as the number of working women increased, with many women arguing that changing their surnames could disrupt their careers and workplace relations.

The U.N. Committee on the Elimination of Discrimination against Women urged Japan in 2009 to adopt a system allowing for the choice of different surnames for married couples.

But Diet debate on allowing couples to retain their surnames after marriage stalled, with lawmakers opposed to the move arguing that the use of separate surnames by couples would undermine family cohesion and traditional family values.