Will or No Will: How It Changes a Japanese Inheritance for Overseas Families

Families dealing with a Japanese estate from abroad usually discover the importance of a will in the worst possible way: months in, when the process has stopped because a cousin in a third country will not return a signed form.

This article sets out what actually differs between an estate with a will and one without, in the specific context of overseas heirs and Japanese real estate. It also covers the question that foreign families almost always miss — which country's law governs the succession in the first place.

At a glance

Question	No will	With a valid will
Who decides who gets what?	All heirs, unanimously	The deceased, in the will
Whose signature is needed?	Every heir, certified	The executor, if one is named
What stops the process?	One heir who will not or cannot sign	Rarely anything procedural
Is a court step involved?	No, unless heirs go to mediation	Verification for a handwritten will, unless it was lodged with the Legal Affairs Bureau
Can close family still claim?	They take their statutory share	Yes — a reserved share, claimed in money
Typical elapsed time, overseas family	6 months to several years	Often 2 to 6 months

What happens with no will

If there is no will, Japanese law sets out who the heirs are and what fraction each takes. Those shares are the starting point, not the outcome: the heirs are free to divide the estate differently if they all agree.

Agreement is recorded in a division agreement (遺産分割協議書). Every heir must sign it and certify their signature. A partly signed agreement is not partly effective — it has no effect at all.

For a family living in one country, this is a Sunday afternoon and a trip to a local office. For a family spread across three countries, each heir must find a notary or a Japanese consulate, certify their signature, and post certified originals to Japan. Every additional heir adds a country, a postal round trip, and a chance that a document is rejected and has to be redone.

Two situations make it worse. If an heir has died, their own heirs step into their place, so the number of signatures grows with every generation that passes. And if an heir lacks legal capacity, a court-appointed representative must be involved before anything can be signed.

The 2024 partial remedy

Japan made inheritance registration compulsory in April 2024, and introduced a stopgap filing — heir reporting registration (相続人申告登記) — that a single heir can file alone. It records that you are an heir and satisfies the registration obligation, so the fine does not apply while the family is still negotiating.

It does not transfer ownership and it does not let you sell. It buys time. We cover it, and the document substitutes foreign heirs need, in our guide to inheritance registration for foreign heirs.

What changes when there is a will

A valid will replaces the unanimous-agreement requirement with an instruction. That single change is why estates with wills move so much faster.

The bigger practical gain is the executor (遺言執行者). If the will names one, that person has authority to carry out the will — dealing with the registration of the property, and with banks — without gathering signatures from every heir in every country.

For an overseas family this is the difference between one person completing a task and eight people coordinating across time zones. If you are advising an older relative who owns Japanese property and has family abroad, naming an executor is the single most useful thing they can do.

The three types of Japanese will, and the one that saves months

Type	How it is made	Court verification needed?
Handwritten (自筆証書遺言)	Written by hand by the testator	Yes — unless lodged with the Legal Affairs Bureau under the storage system
Notarial (公正証書遺言)	Made at a notary office with witnesses; the original is kept there	No
Sealed (秘密証書遺言)	Contents kept secret, existence certified by a notary	Yes

Verification (検認) is not approval

A handwritten will normally has to go through verification at the family court before it can be used. This is commonly misunderstood: verification records the form and content of the document and prevents later alteration. It does not decide whether the will is valid.

What matters to an overseas family is the practical effect. Verification requires the court to notify all heirs, which means assembling the same proof-of-heirship documents you were trying to avoid, and waiting. It is normal for this to add months. Opening a sealed handwritten will without the court is also a mistake — the will is not automatically void, but there is a penalty, and it complicates matters.

The storage system removes that step

Since 2020 a handwritten will can be lodged with the Legal Affairs Bureau under a formal storage system. The bureau checks the formal requirements, stores the original, and a will held this way does not require court verification.

For a Japanese national with family abroad who does not want the cost of a notarial will, this is the practical middle path: cheaper than a notarial will, and it removes the step that hurts overseas heirs most.

What a will cannot do: the reserved share

A will does not give complete freedom. Close family members — broadly the spouse, children, and in some circumstances parents — have a reserved share (遺留分). Siblings do not.

Since the 2019 reform, a reserved share claim is a claim for money, not for a piece of the property itself. This is a significant improvement for anyone dealing with real estate: a disappointed heir can no longer end up as an unwanted co-owner of a house you are trying to sell. They are owed a sum instead.

The claim is also time-limited, and the periods are short — measured from when the person learns of the inheritance and of the gift or bequest that reduces their share. If you think you may be affected, on either side, take advice early rather than assuming silence has settled it.

The question foreign families always miss: whose law applies?

Everything above describes Japanese succession law. Whether Japanese succession law governs your case at all is a separate question.

Japan's conflict-of-laws statute — the Act on General Rules for Application of Laws — points, for succession, to the national law of the deceased. So if the person who died was a citizen of another country, the law of that country may govern who inherits and in what shares, even though the house is in Japan.

Three consequences follow.

• A will valid abroad may work for the Japanese property. It is not automatic, and how it is proved to a Japanese registry is a technical question, but a foreign will is not simply disregarded.
• The shares may not be the Japanese ones. If the deceased's national law gives different shares, that is what applies to the succession, not the Japanese fractions.
• Procedure stays Japanese regardless. Whoever inherits, the property is registered under Japanese registration procedure, on Japanese deadlines, with Japanese documents. Japanese inheritance tax rules also apply on their own terms — see our inheritance tax guide for who is actually liable.

There is a further wrinkle. Some countries' rules point back to the law of the place where the property sits, which can return the question to Japanese law for the real estate. This is genuinely specialist territory. The useful takeaway is not the doctrine but the instruction: if the deceased was not a Japanese national, ask a lawyer which law governs before anyone starts drafting a division agreement. Families have completed an entire agreement under the wrong assumption and had to start again.

If you are planning ahead rather than reacting

Much of the difficulty described here is avoidable at the drafting stage. For an owner of Japanese property whose family lives abroad:

1. Name an executor. The largest single saving in time and stress.
2. Use a notarial will, or lodge a handwritten one with the Legal Affairs Bureau. Either removes the court verification step.
3. Deal with the Japanese property explicitly. A will that covers assets in general, drafted in another country, may leave the Japanese registry unsure what to do with a specific parcel of land.
4. Tell the family where the will is. A perfect will nobody can find is worth nothing, and the storage system includes a way for heirs to check whether one exists.
5. Keep a list of Japanese assets. Bank accounts, the property, and the location of the deeds. Heirs abroad frequently do not know what exists.

A note on advice

This article describes general principles so you know what to expect and what to ask about. It is not legal advice. Which law applies, whether a foreign will can be used for Japanese property, and how reserved shares work in your family all depend on specific facts. Wills and succession disputes are handled by lawyers, and property registration by judicial scriveners (司法書士). Confirm your position with an appropriate professional before acting.

How Japan YES helps

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