Japan Marriage Condition: Legal Requirements, Civil Code Rules

Marriage in Japan is governed strictly by civil law. Unlike many Western countries where religious or non-secular wedding ceremonies hold legal weight, a marriage in Japan is legally binding only when official registration paperwork is submitted and accepted at a municipal government office (city hall or ward office).

Whether both partners are Japanese citizens, one partner is a foreign national, or both are foreign residents, understanding the legal Japan marriage condition rules under the Japanese Civil Code is essential for a valid marriage.

Core Legal Conditions Under the Japanese Civil Code

To contract a lawful marriage in Japan, both individuals must satisfy specific eligibility conditions outlined in Articles 731 through 737 of the Japanese Civil Code:

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| Civil Code Condition              | Requirement Detail                                                |
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| Minimum Age                       | Unified at 18 years old for both men and women.                    |
| Parental Consent                  | No longer required for 18-year-olds (adult majority age).         |
| Marital Status                    | Strictly monogamous; polygamy is illegal under Japanese law.      |
| Consanguinity Prohibition         | Direct blood relatives, siblings, and close lineage banned.       |
| Remarriage Waiting Period (Women) | Reduced to 100 days following previous divorce/dissolution.       |
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1. Unified Minimum Legal Age

Following Civil Code reforms, the legal age of majority in Japan is 18 years old. The legal marriage age is unified at 18 years of age for both men and women. Because individuals aged 18 are recognized as legal adults, parental consent is no longer required.

2. Single Marital Status (Monogamy)

Plural or polygamous marriages are prohibited in Japan. Both partners must prove they are legally single, divorced, or widowed before registering.

3. Remarriage Waiting Period for Women

Under Article 733 of the Civil Code, women who have previously been married must wait 100 days after a divorce or annulment before remarrying. This provision exists to prevent legal disputes regarding paternity if a child is born shortly after a prior marriage ends.

4. Direct Family Lineage Prohibitions

Marriage between close blood relatives—such as parents, children, siblings, grandparents, and grandchildren—is strictly forbidden. However, marriage between first cousins is legally permitted under Japanese civil law.

Marriage Conditions for Foreign Nationals in Japan

Foreign citizens can legally marry in Japan, whether marrying a Japanese national or another foreign resident. However, international couples must satisfy a dual legal threshold: meeting Japan's marriage conditions and remaining eligible under the laws of their home country.

Required Documents for International Registration

To register a marriage at a local Japanese ward or city office, foreign nationals must submit specific original documents alongside complete Japanese translations:

Marriage Notification Form (Kon'in Todoke - 婚姻届): The primary registration document, which must be signed by both partners and two adult witnesses (aged 18 or older) of any nationality.
Valid Identification: Original passports for foreign nationals, or a residence card / My Number Card if living in Japan.
Affidavit of Competency to Marry (Kon'in Yoken Gubi Shomeisho - 婚姻要件具備証明書): An official document issued by the foreign partner's embassy or consulate in Japan proving they are legally free to marry under their home country's laws.
Certified Birth Certificate: Required for foreign partners to establish parental details and full legal name.
Japanese Family Register (Koseki Tohon - 戸籍謄本): Required exclusively if one partner is a Japanese citizen.

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| REGISTRATION STEP-BY-STEP PROCESS                                                                |
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| STEP 1: EMBASSY AFFIDAVIT                                                                        |
| Foreign partner obtains Affidavit of Competency to Marry from their home embassy in Japan.       |
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| STEP 2: DOCUMENT TRANSLATION                                                                     |
| Translate foreign birth certificates and affidavits into Japanese (friend or self-translation).  |
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| STEP 3: WITNESS SIGNATURES                                                                       |
| Obtain signatures from two witnesses (aged 18 or older) on the Kon'in Todoke form.               |
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| STEP 4: MUNICIPAL FILING                                                                         |
| Submit all paperwork at the municipal city/ward office. Registration is completed same-day.      |
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Post-Marriage Visa Status (Spouse of Japanese National)

Registering a marriage in Japan does not automatically grant residency or citizenship to a foreign spouse. Foreign nationals who marry a Japanese citizen must apply separately for a Spouse of a Japanese National (Nihonjin no Haigusha) visa through the Immigration Services Agency of Japan.

Key Spouse Visa Requirements

Proof of Genuine Marriage: Photos together, chat logs, joint travel records, and detailed personal statements detailing the relationship history.
Financial Guarantee: Proof of steady employment, local tax payments, or sufficient bank balances from the Japanese sponsor or applicant.
Permanent Residency Pathway: Spouses of Japanese citizens who have been married for at least 3 years and have resided continuously in Japan for at least 1 year become eligible to apply for Permanent Residency (PR).