Inheriting from a Japanese family member while living abroad: how to collect the koseki you need

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Which describes you?

• Child of the deceased (with or without Japanese nationality) → 3, 4
• Foreign spouse of the deceased → 2, 5
• Grandchild, brother, sister, nephew or niece → 3
• Worried about deadlines → 7

1. Why one koseki is not enough

Banks and the Legal Affairs Bureau must be sure that no heir has been missed, such as a child from an earlier marriage. The latest koseki often does not show this.

A person’s records are usually spread over several registers:

• Marriage: a new koseki is usually created, and the person leaves their parents’ register.
• Moving the honseki: a new koseki is created at the new place, and the old one is closed.
• Rewriting: koseki were rewritten in 1957 and again when computerized in 1994. The old version is kept as a kaisei-gen koseki (改製原戸籍). Some past entries, such as a child who had already married out, were not copied to the new version.

So you usually need a continuous set of records from birth to death. When you request them, say that you need “all records from birth to death for an inheritance procedure.”

2. Who inherits under Japanese law

The spouse is always an heir. The others inherit in this order. A later group inherits only if there is no one in the earlier group.

Nationality does not matter. A foreign spouse, or a child without Japanese nationality, is still an heir. So is a child from an earlier marriage, even one you have never met.

Exceptions: when someone in the table is not an heir

• Disqualification (Civil Code, Article 891): a person loses the right to inherit automatically in serious cases, for example if they were sentenced for killing or trying to kill the deceased, or forged or destroyed the will.
• Removal (Articles 892 and 893): the family court can remove an heir at the request of the deceased, by will or during their lifetime, for example for abuse or serious insult. This applies to children and parents, not to brothers and sisters. The removal is recorded in the removed person’s koseki.
• Renunciation (Article 939): a person who renounces at the family court is treated as never having been an heir.

If a child or sibling was disqualified or removed, their children inherit in their place, as when the heir died earlier. This does not happen when someone renounces.

3. Which koseki you need, case by case

The further down the order, the more records you need. As a general guide:

Spouse and children inherit

• The deceased’s records from birth to death
• Each heir’s current koseki, if they have one
• If a child died earlier: that child’s records from birth to death, to find their children (the grandchildren), and each grandchild’s current koseki

Parents inherit (no children)

• The deceased’s records from birth to death, which also show there were no children
• If a child died earlier: that child’s records from birth to death, to show that they left no children
• Each living parent’s current koseki
• If grandparents inherit: a koseki showing the parents’ deaths

Brothers and sisters inherit

• The deceased’s records from birth to death
• If a child died earlier: that child’s records from birth to death
• Both parents’ records from birth to death, to find every sibling, including half-siblings
• Records showing that the parents, grandparents and any older ancestors have died
• Each living sibling’s current koseki
• If a sibling died earlier: that sibling’s records from birth to death, and the current koseki of their children (the nephews and nieces)

If the deceased, a parent or another ancestor was adopted, the records of both the birth parents and the adoptive parents must be checked. Where very old registers no longer exist, the city office may issue a certificate saying so, which some offices accept instead.

Banks and other offices may ask for other documents. Check with each office first.

Heirs who are not in a koseki

A foreign national has no koseki. Their link usually appears in the Japanese family member’s koseki instead:

• Foreign spouse: the marriage, with the spouse’s nationality, name and date of birth, is recorded in the Japanese spouse’s koseki (see how international marriage is recorded in the koseki).
• Child who lost Japanese nationality: the loss is recorded if it was reported to Japan. If it was never reported, the child may still appear in the koseki as a member.
• Child born abroad without reserving Japanese nationality: such a child may never have been entered in the koseki at all.

If an heir is not in any koseki, documents from their country, such as a birth certificate, are needed to prove the relationship. These cases can become complex.

4. Requesting the records from abroad

Who can request them

• Spouse, children, grandchildren, parents, grandparents: yes, as the spouse or a lineal relative (Article 10 of the Family Register Act). This includes a foreign spouse and a child without Japanese nationality.
• Brothers, sisters, nephews, nieces: only with a reason, such as exercising your rights as an heir (Article 10-2). The city office may ask for proof that you are an heir.

The nationwide counter service does not help from abroad

Since March 1, 2024, koseki from anywhere in Japan can be requested at one city office counter. But you must come in person with a photo ID. Requests by mail or through a representative are not accepted.

From abroad, you request each register by mail from the municipality that keeps it. Each register shows the one before it, so the records are traced back one by one, often across several municipalities. For the steps, see how to get a koseki from overseas.

5. Can you use the Legal Heir Information Certificate?

In inheritance procedures, a certified chart of the heirs issued by the Legal Affairs Bureau (法定相続情報一覧図の写し) can sometimes be used instead of the bundle of koseki. However, the Legal Affairs Bureau states that this system cannot be used if the deceased or an heir does not have Japanese nationality. If even one heir is a foreign national, you usually submit the original koseki, together with a family chart and documents from the heir’s country, to each bank or office.

6. Documents you may need besides the koseki

In Japan, heirs usually stamp the agreement on dividing the estate with a registered seal and attach a seal certificate. People living abroad cannot register a seal, so other documents are used:

• Japanese living abroad: a signature certificate (署名証明) from a Japanese embassy or consulate. You must sign in front of a consular officer; mail and proxy applications are not accepted.
• Foreign nationals: usually a signature certified by a notary public in your country. A former Japanese national may be able to get a signature certificate in some inheritance cases; ask the embassy or consulate.
• Proof of address: for example, a certificate of residence from the embassy (Japanese) or a notarized statement (foreign nationals).
• Japanese translations of documents in other languages.

Requirements differ by bank and office. Ask each one before you get documents notarized. For the opposite case, see notarization and apostilles in Japan.

7. Deadlines to keep in mind

Collecting koseki from abroad can take months. Keep these deadlines in mind from the start (as of November 2026):

• 3 months: to renounce or accept with limits at the family court, from when you learn that the inheritance has started for you (Civil Code, Article 915). An extension can be requested.
• 10 months: to file an inheritance tax return, if tax is due, from the day after learning of the death.
• 3 years: to register inherited real estate, from when you learn you acquired it (mandatory since April 1, 2024; for earlier inheritances, by March 31, 2027). A fine of up to 100,000 yen may apply without a valid reason.

If the deceased may have had debts, the 3-month deadline matters most. Get advice early.

8. Who can help with what

Whoever you work with, the koseki of the deceased are the starting point.

Disclaimer: This article is provided for general information only and is not legal or tax advice on any individual case. It does not cover inheritance governed by foreign law. The information is based on sources available as of November 10, 2026. Laws, guidelines and their application may change without notice. TKG Immigration Consulting Office accepts no liability for any loss or damage arising from the use of this information. In case of any difference between our English descriptions and the original Japanese texts, the Japanese texts prevail.