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Married Names and Japan's Single-Surname Rule

Japan's single-surname rule requires Japanese-Japanese couples to share one surname, while Japanese-foreign couples are exempt and keep separate surnames by default.12 This article covers the documentation mechanics of that rule: which registry changes, which form starts it, and which court step the exception route needs.

Confirm current details with official sources

Procedures, fees, and requirements can change. Confirm current details at the Ministry of Justice site.

Overview​

The rule lives in the Civil Code and takes effect through the family register. At marriage, a Japanese-Japanese couple selects either spouse's surname, and that choice reshapes both spouses' register entries.12 A Japanese-foreign couple makes no such choice, because the foreign spouse is not entered on the register as a member.2

Family-law substance such as divorce procedure, custody, and inheritance belongs to The Four Divorce Paths, Marriage to a Japanese National, and Koseki: Japan's Family Register Explained. This article stays on the register mechanics.

The Single-Surname Rule for Japanese Couples​

Article 750 of the Civil Code requires spouses to use one surname, the husband's or the wife's, determined by mutual choice at marriage.1 The statute is gender-neutral on its face, though reported practice shows around 95 percent of couples choosing the husband's surname.3

The choice is recorded through marriage registration. The 婚姻届 (kon-in todoke, "marriage registration form") creates a new 戸籍 (koseki, "family register") for the couple, unless one spouse already heads an existing register, which the other spouse then joins.23

Japanese-Foreign Couples Are Exempt​

A foreign spouse is not entered on the koseki as a member, so the single-surname requirement does not attach to the couple.2 The foreign spouse keeps their original surname for all Japanese-side purposes by default.2

The marriage is noted on the Japanese spouse's koseki with the foreign spouse's name alongside it. That notation records the fact of marriage without creating a shared surname.2 Related registration detail is covered in Marriage Between Two Foreigners in Japan and Foreigner on Koseki Edge Cases.

Your residence card surname does not change at marriage

Marriage alone changes nothing on a foreign spouse's residence card. A card update needs a home-country legal name change first, as described in Updating the Name on a Residence Card.2

A Foreign Spouse Adopting the Japanese Surname​

A foreign spouse who wants to use the Japanese spouse's surname files a separate petition with the 家庭裁判所 (katei saibansho, "family court") for permission to change the surname.4 The court weighs the petition against the statutory unavoidable-grounds standard rather than granting it on request.4

Only after the court grants permission does the change enter Japanese-side records.4 Practitioner sources describe most foreign spouses as keeping their original surname, with the typical friction being Japanese institutions that assume otherwise and need correction.3

The Separate-Surname Reform Debate​

Whether Japanese-Japanese couples should be allowed to keep separate surnames, known as 選択的夫婦別姓 (sentaku-teki fūfu bessei, "optional separate surnames for married couples"), has been debated in the Diet and the press for years without enactment (as of 2026-09; confirm current status through current Diet reporting).5 This article takes no position on the outcome. Readers tracking the debate should follow current legislative reporting rather than treating any summary here as final.5

Good to know​

Some institutions assume you took your spouse's surname​

Counter staff accustomed to the single-surname default sometimes address a foreign spouse by the Japanese surname. A calm correction with photo ID resolves it, and the correction tends to stick once the institution's record is fixed.3

Divorce restores the prior surname path by default​

After divorce, the surname question returns to koseki filing rules, whose detail belongs to the divorce articles. Keep marriage and divorce certificates accessible, since each later counter asks for the paper chain behind the current name.2

See also​

References​

Footnotes​

  1. Civil Code (民法), Art. 750 (surname of husband and wife), via e-Gov law portal. https://elaws.e-gov.go.jp/document?lawid=129AC0000000089 ↩ ↩2 ↩3

  2. Family Register Act (戸籍法), via e-Gov law portal. https://elaws.e-gov.go.jp/document?lawid=122AC0000000224 ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8 ↩9

  3. Ministry of Justice. Family-register procedures and marriage registration guidance. https://www.moj.go.jp/ ↩ ↩2 ↩3 ↩4

  4. Courts in Japan. Family court petition procedures for name-change permission. https://www.courts.go.jp/ ↩ ↩2 ↩3

  5. National Diet and major-press coverage of the 選択的夫婦別姓 (optional separate-surname) legislative debate, as status reporting. Cited as debate-status only, not for legal substance. ↩ ↩2