A Tokyo court on Monday upheld a national law that forces couples to use the same surname upon marriage, rejecting claims over its unconstitutionality.
The lawsuit against the central government was brought by Yoshihisa Aono, the 47-year-old president of software development firm Cybozu Inc., and three others seeking a change to the Family Register Law that would give them the right to use their premarital surnames.
The other three plaintiffs, who declined to be named, are a woman in her 20s and a common-law couple.