Japanese Koseki (Family Register) Translation for Immigration

What Is a Japanese Koseki (Family Register)?

A koseki is Japan’s official family registry, a single document that records an entire household’s births, marriages, deaths, adoptions, and legal relationships. Rather than holding separate certificates for each life event, a koseki functions as a consolidated master record. A “family membership certificate” typically refers to an extract that shows the relationships linking several members under one household. Immigration authorities rely on the koseki because it demonstrates familial ties clearly and authoritatively, which is exactly what a spouse visa or family-based green card petition demands.

How Koseki Formats Differ by City and Ward

Although all koseki follow the national Family Register Act, the printed layout varies slightly among Japan’s approximately 1,700 municipalities. Some city or ward offices use landscape orientation; others use portrait. Column headings, seal placements, and shading differ. Lekhak’s AI translation reads these variations on the fly and outputs a single English DOCX that preserves the underlying information, irrespective of the issuing ward. From past translations of documents originating in Osaka’s Joto Ward and elsewhere, we have observed that the core data, names, dates, relationships, and domicile, remains structurally consistent.

Common Japanese Terms in a Koseki

A koseki is packed with standardised column headings and fields. Recognising these terms speeds up your own review while you wait for a translation. Below are the entries most frequently encountered in family registers submitted for immigration petitions.

Japanese (Kanji/Kana)	Romanisation	English
戸籍	koseki	family register
本籍地	honsekichi	registered domicile
筆頭者	hittousha	head of register
氏名	shimei	full name
生年月日	seinengappi	date of birth
父	chichi	father
母	haha	mother
配偶者	haigūsha	spouse
死亡	shibō	death
除籍	joseki	removal from register

Why Translate a Koseki for an Immigration Petition?

The driving use case we see is the family-based immigration petition. When a US citizen or lawful permanent resident files Form I‑130 for a Japanese spouse, USCIS requires an English translation of all foreign-language supporting documents. The koseki serves as the primary proof of the marital relationship because it records the marriage, the spouses’ names, and often the birth of any children, all in one official record. The U.S. Department of State’s reciprocity schedule for Japan specifically lists the koseki tohon as the acceptable document for marriage, birth, and death records. Immigration officers scan the translated entries to confirm the relationship is genuine and that there are no inconsistencies with other evidence.

AI Translation vs. Human-Certified Work: When Each Fits

Lekhak’s AI translation turns a scanned or photographed koseki into a clean English DOCX in minutes. That output is ideal for understanding your own record, sharing a draft with an attorney, or preparing a summary before you commit to a final submission. However, USCIS policy requires that any foreign-language document submitted with a petition be accompanied by a full English translation and a certification by the translator. An AI‑generated translation on its own does not satisfy the certification requirement because it does not include a translator’s signed statement attesting to competence and accuracy. If you intend to file the koseki with USCIS or an embassy, you will need a separate certified translation produced by a qualified human translator. What many users do is run the koseki through Lekhak first to get a fast, readable DOCX; they then hand that draft to a certified translator who can finalise and certify it efficiently. This saves time and cost during the preparation phase.

What Lekhak’s AI Translation Produces

The output after Lekhak processes a koseki is a single DOCX file. It preserves the original table layout, rows, columns, and the logical grouping of household members, so the English version mirrors the structure of the Japanese original. All names, dates (converted from Japanese era years to Gregorian where necessary), and relationship statuses appear in English. Any official seals (hanko) are described in the text. The file arrives in minutes after upload. It does not include a translator’s certificate, notarisation, or an affidavit. There is no PDF, and no physical courier, everything is digital and self‑service. That makes the DOCX suitable for internal review, a legal consultation, or as a working draft.

When You Need Notarisation, Apostille, or Embassy Attestation

For uses beyond translation, such as submitting the original Japanese koseki abroad, a separate authentication step may be required. Japan is a party to the Hague Apostille Convention, so for most destination countries (including the US) the Japanese Ministry of Foreign Affairs can affix an apostille directly to the koseki; embassy legalisation is seldom needed. This process confirms the seal and signature on the original document, not its translation. Lekhak does not offer notarisation, apostille, or attestation services, neither self‑serve nor as a managed arrangement. You handle authentication through the municipal office that issued the koseki and, if an apostille is needed, through the appropriate Japanese authority.

How to Obtain a Copy of Your Koseki from Japan

If you no longer hold the original koseki, you can request a copy from the municipal office that holds your registered domicile (honsekichi). The request can be made by mail, through a proxy in Japan, or, in some cities, via an online portal. You will need to submit an application form, proof of identity, and a processing fee. The municipal office then issues either a koseki tohon (full record) or koseki shohon (extract of individual matters). Overseas residents often authorise a relative or a legal representative in Japan to obtain the document on their behalf. Processing times and fees vary by ward; the municipality’s official website is the most reliable source for current details.

FAQ

What’s the difference between koseki tohon and koseki shohon?

A koseki tohon is the complete family register showing all members and all recorded events for a household. A koseki shohon is an extract that lists only selected individuals, for instance, just the head of the register and the applicant. Immigration petitions usually request the tohon because it provides a full picture of the family unit.

Does USCIS accept machine-made or AI translations of a koseki?

No. USCIS requires a translation accompanied by a translator’s certification. Because Lekhak’s AI output does not include a signed statement from a human translator, it cannot serve as the final certified translation. Many applicants use an AI draft as a review copy, then have a certified translator finalise the submission version.

How long does Lekhak take to translate a koseki?

Lekhak processes a koseki in minutes after you upload the file. You receive the English DOCX immediately, there is no 24‑hour turnaround because the translation is entirely AI‑driven. Speed may vary slightly with file size and server load, but the delivery is nearly instant in most cases.

Can I use Lekhak’s translation as my official submission for a spousal visa?

No. Because the translation lacks a translator’s certification, it does not meet the evidentiary standards of USCIS or most embassies for spousal visa petitions. Use Lekhak’s output for your own understanding or as a draft to share with an attorney; obtain a separate certified translation for the actual filing.

What format will I receive from Lekhak, PDF, image, or editable file?

You receive a single DOCX file. The document is fully editable, so you can review and annotate the translation before forwarding it to a certified translator or legal representative. Lekhak does not deliver PDFs, images, or any form of physical document.

How do I get a certified translation of my koseki if Lekhak doesn’t offer one?

Certified translations come from independent translators or translation agencies that employ qualified individuals who sign a statement of accuracy. You can locate a certified translator through professional directories or a law firm that handles immigration cases. Lekhak does not arrange or recommend any specific provider.

Will my koseki’s seal (hanko) and era dates be translated correctly?

Yes. Lekhak’s AI identifies official seals and describes them in the English text. Japanese era years (such as Heisei or Reiwa) are converted to Gregorian years where the context is clear, though both may appear in the output for reference. The translation notes any stamps that mark the issuing authority.

Does Lekhak keep my personal information from the koseki secure?

Lekhak processes files on secure servers and deletes them after translation. Personal data is not used for training or shared with third parties. For details, refer to the privacy policy on lekhak.app.

Can I use Lekhak to translate only part of my koseki, like a specific entry?

Yes. You can upload the full koseki and then edit the resulting DOCX to extract only the relevant sections. Lekhak translates the entire document as received; selective translation is done manually by you after delivery.

What if my koseki contains handwritten entries or mixed scripts?

Lekhak’s AI handles mixed printed and handwritten Japanese, though heavily cursive or very low‑contrast handwriting may reduce accuracy. The DOCX output will faithfully represent what the system reads; you can compare it against the original and request a certified translator’s review for any uncertain fields.