The top court on Wednesday again ruled that legal provisions forcing married couples to use the same surname are constitutional, upholding a Supreme Court judgment from 2015.
The latest decision on a more than century-old provision based on the Civil Code and the family register law dismissed requests filed by three couples in 2018 to keep their separate surnames after local governments refused to accept their marriage registrations.
The decision handed down by presiding Justice Naoto Otani at the Supreme Court's Grand Bench, composed of all 15 justices, came at a time when families have become more diverse and public opinion on surname sharing has shifted in Japan.