Plaintiffs contesting family laws that require spouses to choose a single surname expressed shock and anger at Wednesday’s Supreme Court ruling, saying it sets a bad precedent and will force more women to suffer the misery of having to change their name upon marriage.

In a vote of 10 to 5, the nation’s top court dismissed claims by five women seeking the right to retain their maiden names after marriage. The court said the century-old Civil Code provision requiring couples to share a surname — they can choose which — is “established in Japanese society,” and that the matter should be taken up in the Diet, not the courts.

“I’m sad, I’m in pain,” a weeping plaintiff Kyoko Tsukamoto told a news conference in Tokyo following the ruling. She goes by Tsukamoto, her maiden name, although her husband’s name must be used on legal documents. “My name is something I can’t give up.”

Fellow plaintiff Kaori Oguni expressed anger, saying the reasoning for the ruling was “horrible.”

“This means that future generations of women will be shouldered with the same suffering we have gone through,” Oguni, a 41-year-old mother of a 6-year-old daughter, said. “I’ve told my daughter of (the injustice of) the Japanese marriage system for years. I’m at a loss for how to explain today’s ruling to her.”

Fujiko Sakakibara, a lead lawyer in the case, said the ruling reflects Japan’s poor participation of women in society, including in the judiciary.

“The percentage of female judges in the Supreme Court is only 20 percent now, which has resulted in this outcome.”

In a separate case, the Supreme Court ruled that a Civil Code provision prohibiting female divorcees from remarrying within six months of their divorce is unconstitutional.

Tomoshi Sakka, a lawyer representing the plaintiff, a woman in her 30s, said the Diet should swiftly change the law. In its ruling Wednesday, the court said the period in which a divorcee cannot remarry should be shortened to 100 days from the current six months, citing advances in medical technologies, such as DNA tests, which have made the paternity of children much easier to ascertain.

For women wishing to remarry within 100 days after a divorce, Sakka said, the government should allow them to do so as long as they have obtained proof from a medical doctor that they are not pregnant.

“We request that the government issue a notice allowing such women to remarry, given that the advances in medical and other scientific technologies (in shortening the ban) are cited in the ruling,” Sakka said.