Miyake & Partners | Japanese Law Explained | October 2026

Many people in Japan die without a will. When that happens, the law decides who inherits and in what shares. The rules are simple on paper, but they often surprise families, especially international ones. A partner may get nothing, a stepchild may be left out, and strict deadlines start running from the day of death. Knowing the default rules now is the easiest way to avoid unpleasant surprises later.

Does Japanese law apply at all?

Not always. Under Japan’s conflict-of-laws rules, inheritance is generally governed by the law of the deceased person’s nationality, not by where they lived or where the property is. For a Japanese national, that means Japanese law. For a foreign national living in Japan, it usually means the law of their home country. However, some countries’ laws point back to Japanese law (for example, for land in Japan or for someone domiciled here), and in that case Japanese law applies after all.

This article explains the Japanese default rules. If the deceased was not a Japanese national, the first step is to confirm which country’s law applies.

Who are the heirs?

The spouse is always an heir. Other relatives inherit alongside the spouse in a fixed order. A later group inherits only if there is no one in an earlier group.

First: children. If a child has already died, that child’s children (the grandchildren) take their place.
Second: parents. If there are no children or grandchildren, the deceased’s parents inherit. Grandparents inherit only if both parents have died.
Third: brothers and sisters. If there are no children and no parents or grandparents, siblings inherit. If a sibling has died, their children (nieces and nephews) take their place.

A common-law partner is not an heir. A person who formally renounces the inheritance is treated as if they had never been an heir.

How is the estate shared?

The statutory shares depend on who survives the deceased:

Spouse and children: spouse one half; children share the other half.
Spouse and parents: spouse two thirds; parents share one third.
Spouse and siblings: spouse three quarters; siblings share one quarter.
No spouse: the relatives in the highest group share everything.

Where there are several children, parents or siblings, they generally share their portion equally. For example, if a man dies leaving a wife and two children, the wife takes one half and each child takes one quarter.

These shares are a fallback, not a requirement. If all the heirs agree, they can divide the estate in any way they choose. Every heir must take part in that agreement, which is why one heir living abroad or refusing to cooperate can bring the whole process to a halt.

Five questions families often overlook

Check	Why it matters
Is there an unmarried partner?	A common-law (unmarried) partner is not a legal heir, however long the relationship. Without a will, they receive nothing under the default rules.
Are there stepchildren?	A stepchild is not a child of the deceased for inheritance purposes unless they were formally adopted. Many blended families discover this too late.
Did any child die before the parent?	That child’s own children (the grandchildren) step into their place and share their portion.
Does anyone want to renounce?	A person who renounces is treated as never having been an heir. This can pass the inheritance to the next group of relatives, so it should be planned, not done in a hurry.
Do the heirs want a different split?	The statutory shares are a fallback. The heirs can agree on any division they like, but every heir must take part in the agreement.

After a death: key deadlines

Several time limits start running soon after a death. Recent reforms have made property registration mandatory:

Within 3 months: an heir who wants to renounce must file with the family court for the deceased’s last address. The period runs from when the heir learns that the inheritance has opened. The court can extend it if more time is needed to investigate the estate.
Within 10 months: if the estate exceeds the basic exemption (JPY 30 million plus JPY 6 million per statutory heir), an inheritance tax return must be filed and the tax paid.
Within 3 years (since 1 April 2024): anyone who inherits real estate must register the inheritance. Failure without good reason can lead to a fine of up to JPY 100,000.
By 31 March 2027: the registration duty also applies to inheritances that happened before April 2024. Property inherited before that date must be registered by 31 March 2027.

To reduce paperwork, heirs can ask the Legal Affairs Bureau for a certified chart of statutory heirs. Banks and other institutions can accept it in place of a large bundle of family register documents.

How we can help

Our cross-border team advises in English on Japanese inheritance matters. We can confirm which country’s law applies, identify the legal heirs, prepare estate division agreements, handle renunciations and property registration, and coordinate with tax advisers in Japan and abroad. We also help clients make a will so that their family does not have to rely on the default rules. If you have questions about an inheritance in Japan, please contact us.

Cross-Border Team: cross-border@miyake.gr.jp
Yasuchika Fukuda, Partner: y-fukuda@miyake.gr.jp

NOTICES

THIS ARTICLE IS PROVIDED FOR GENERAL INFORMATION PURPOSES ONLY AND DOES NOT CONSTITUTE LEGAL ADVICE. YOU SHOULD SEEK SPECIFIC ADVICE BEFORE ACTING ON ANY MATTER DISCUSSED IN IT.

THIS ARTICLE IS BASED ON THE LAWS AND REGULATIONS IN FORCE AS AT THE DATE OF PUBLICATION, WHICH MAY CHANGE AS A RESULT OF SUBSEQUENT AMENDMENTS.