The Supreme Court has set Dec. 16 to rule on Civil Code provisions that prohibit married couples from using separate family names and bar women from remarrying for a period of six months after divorce, court officials said.

The rulings in two separate cases, scheduled at 3 p.m., will be the first decisions by the top court's grand bench on the constitutionality of the provisions, which date back more than a century. The government may be prompted to revise the code depending on the results.

In the family name case, Kyoko Tsukamoto, an 80-year-old former high school teacher, and four others argued that a provision obliging married couples to choose one family name "forces (people) to change their surnames and therefore infringes on their rights."

But the state countered that the choice of a family name is left to each couple, and that the provision does not place one family name over the other.

In the suit over remarriage, a woman in her 30s from Okayama Prefecture took issue with the Civil Code provision that prohibits women from remarrying within six months of divorce. The provision is meant to avoid confusion when presuming the identity of a child's father.

The plaintiff had to wait six months after divorce to marry her current husband because of the provision, which she argued runs counter to equality before the law.

The state defended the provision as being reasonable despite its age, in that it is meant to avoid confusion when ascertaining paternity.

The provisions remain in the Civil Code despite calls for their revisions both at home and abroad, while other developed countries are said to have already scrapped similar rules.