A 128-Year-Old Law Is Forcing Couples in Japan to Share a Surname. Americans Are Watching Closely
Across several democracies, family-name rules have become a live policy issue again as governments weigh tradition against individual choice. In Japan, that debate returned to the spotlight on June 23, 2025, when the Supreme Court upheld the country’s same-surname requirement for married couples, keeping in place a rule rooted in the 1898 Civil Code. The decision is getting attention in the U.S. because Americans have their own long-running debates over marriage, identity documents, and naming rights.
Japan’s top court kept the rule in place
Japan’s Supreme Court on June 23, 2025, upheld the legal requirement that married couples share one surname, according to Japanese media reports and prior court records tied to the case. The rule comes from Article 750 of Japan’s Civil Code, which says a husband and wife must adopt either the husband’s or wife’s family name when they marry. In practice, government data has consistently shown that about 95% of couples choose the husband’s surname.
The law has been challenged before. In 2015 and again in 2021, Japan’s Supreme Court also upheld the same-surname system, stating that any change should come from the Diet, Japan’s national legislature. Supporters of reform have pushed for an optional dual-surname system, not a mandate, which would let married couples keep separate legal names if they choose.
What this means inside Japan, and why Americans are noticing
The impact is national, but it is especially visible in big urban areas like Tokyo and Osaka, where more dual-income couples work under professional names built over many years. Japanese lawmakers have not passed a bill creating an optional separate-surname system, and the government has not announced a timetable for doing so. What is confirmed is that couples who want different legal surnames still cannot register a marriage in Japan under current law.
Americans are watching because the issue overlaps with familiar U.S. questions about paperwork, careers, and personal identity after marriage. In the United States, spouses can usually keep separate surnames, hyphenate, or change names through state-level processes, though rules vary by jurisdiction. That contrast has made Japan an international example in legal and academic discussions about whether marriage law should prioritize administrative uniformity or individual choice.
The bigger context behind the dispute
The current rule dates to 1898, when Japan’s modern Civil Code formalized the household registration system known as koseki. Critics, including bar associations and women’s rights groups in Japan, have said the law places a disproportionate burden on women because most women, not men, end up changing their names. Business groups have also argued that mandatory name changes can create extra costs around licenses, payroll records, banking, and published work.
Public opinion in Japan has shifted over time. Major Japanese newspapers, including Asahi Shimbun and Mainichi Shimbun, have reported in recent years that polls show majority support for allowing optional separate surnames. For U.S. readers, the practical takeaway is simple: couples in Japan still need one legal surname to marry, and any change now depends on action by the Diet rather than the courts.
