What is Adult Guardianship in Japan?

Adult Guardianship /Seinen Kouken Seido / 成年後見制度

You have been your child’s protector their entire life. That does not change when they turn 18. But the law’s recognition of your role does. When your child turns 18, your parental authority (shinken / 親権) ends. Legally, your child is now an adult. If your child has an intellectual or developmental disability that limits their ability to make complex decisions, sign contracts, or manage finances independently, a gap opens: the legal protection that parental authority provided is gone, but the need for support has not changed.

Japan’s adult guardianship system (seinen kouken seido / 成年後見制度) is the legal framework designed to fill that gap. A guardian appointed by the family court (katei saibansho / 家庭裁判所) can manage the person’s financial affairs, sign contracts on their behalf, arrange welfare services, and protect them from exploitation.

Guardianship Is Not Mandatory

This is one of the most important things for parents to understand: adult guardianship is not required in Japan.

There is no law that says you must apply for guardianship when your child turns 18. This was baffling to me when I went in for a consultation, as the process of securing guardianship in the United States typically begins before a child turns 18. However, I learned that this is a more nuanced process than I had initially thought.

Many families of people with disabilities choose not to use the guardianship system at all. According to recent data, very few families estimated to need guardianship in Japan actually use it. My counselor informed me that the vast majority of families manage without it for a variety or reasons.

Whether guardianship is right for your family depends on your unique situation. Some families need it, while others find alternatives that work well for them. This article is designed to be a starting guide, helping you understand the system and the options available so you can make an informed decision about what best meets your family’s needs.

Why Some Families Choose Guardianship

There are real situations where guardianship provides important protection:

• Contract protection: Without a guardian, your adult child can legally sign any contract, including phone plans, subscriptions, loans, or purchases they do not understand. Under full guardianship, a guardian can cancel harmful contracts on the person’s behalf.
• Financial management: If your child receives a disability pension, inheritance, or other income, a guardian provides a legal framework for managing that money responsibly, with court oversight.
• Service coordination: A guardian can sign contracts for group home placement, welfare services, and other care arrangements on the person’s behalf.
• Protection from exploitation: People with intellectual disabilities are disproportionately targeted by scams and financial exploitation. A guardian provides a legal shield.
• After the parents are gone: If you are doing oyanaki ato planning (see our article “Planning for Life After You’re Gone”), guardianship ensures that someone with legal authority continues to manage your child’s affairs after you are no longer able to.

Why Many Families Choose Not to Use It

The concerns that keep families from pursuing guardianship are real and valid. The more I spoke with counselors and other parents of adult children with disabilities, the more I realized just how significant this decision is and how carefully it should be considered before making a final decision.

A System Built for a Different Situation

Japan’s guardianship system was originally created primarily with older adults experiencing cognitive decline in mind. It assumes a person who once had full capacity and lost it. For a young person with a lifelong intellectual or developmental disability, the fit is not always right. The person’s needs are different: they may not need someone to take over all decision-making, but rather someone to help with specific things while respecting their own preferences, routines, and choices.

You May Not Get to Choose the Guardian

When you apply, you can name a candidate (kouho sha / 候補者) that you would like the court to appoint. But the family court makes the final decision, and in recent years, professional guardians (lawyers, judicial scriveners, and social workers) have been appointed in the majority of cases. This is especially likely when the person has significant assets or when the family situation is complex. Some family courts, including Tokyo’s, have thresholds above which they are more likely to appoint a professional guardian or require a guardianship support trust.

For many parents, the idea of a stranger, however qualified, taking legal control over their child’s life is deeply uncomfortable. This is one of the most common reasons families hesitate.

Once It Starts, It Does Not Stop

Under the current system (as of 2026), once statutory guardianship is appointed, it generally continues for the person’s entire life. It can only be ended if the person’s decision-making capacity recovers, which for most people with lifelong intellectual disabilities, it will not. This means the fees, the reporting, and the involvement of a guardian continue indefinitely.

The 2026 reform (see the section below) aims to change this, but until the reform takes effect, the lifetime requirement remains.

How It Affects Your Child’s Independence

Under full guardianship (kouken / 後見), the person’s ability to make independent legal decisions is limited. The guardian has the power to cancel contracts the person makes on their own. While this is intended as a protection, it also means the person cannot act independently in legal and financial matters, even for everyday transactions. This is a significant trade-off, and it is worth considering carefully whether the lighter levels of guardianship (hosa or hojo) might provide the protection your child needs while preserving more of their independence.

The Fees Add Up

If a professional guardian is appointed, they receive ongoing compensation from the person’s own assets. These fees continue for the person’s entire life. Over decades, this is a significant cost. More on fees below.

It May Feel Like Losing Your Role

Many parents describe the guardianship process as one of the most emotionally difficult aspects of future planning. You have spent years being the person who understands your child best, advocates for them, and makes sure their needs are met. The idea of a court deciding who has the authority to make legal decisions for your child, potentially someone who has never even met them, can be deeply unsettling.

This hesitation is one of the reasons adult guardianship is rarely used when disabled adults are still young. However, it is important not to rush this decision. Take the time to understand the system, explore the available alternatives, and choose the option that best fits your family’s unique circumstances.

The Two Main Types

1. Voluntary Guardianship (Nin’i Kouken / 任意後見)

This is a contract-based system that the person sets up in advance, while they still have the capacity to understand and sign a contract. The person chooses someone they trust and signs a notarized contract (nin’i kouken keiyaku / 任意後見契約) at a notary office, specifying exactly what decisions the guardian will be authorized to make.

The contract only takes effect when the person’s decision-making ability actually declines. At that point, the family court appoints a supervisor (nin’i kouken kantokuin / 任意後見監督人) to oversee the guardian’s work.

This type lets the family choose the guardian and define the scope of their authority. However, it requires the person to have sufficient capacity to understand the contract, which means it is not available for everyone with a lifelong intellectual disability.

2. Statutory Guardianship (Houtei Kouken / 法定後見)

This is the court-appointed system, and it is the type most relevant for families of people with lifelong disabilities. A family member or other interested party applies to the family court, which evaluates the person’s situation and appoints a guardian.

Under the current system, statutory guardianship has three levels:

• Kouken (後見) / Full Guardianship: For people who have significant difficulty making most decisions on their own. The guardian (seinen koukenin / 成年後見人) has broad authority to act on the person’s behalf for nearly all legal and financial matters.
• Hosa (保佐) / Curatorship: For people who have difficulty making important decisions such as borrowing money, selling property, or accepting an inheritance. The curator (hosanin / 保佐人) must give consent for these major actions, but the person retains independence for everyday decisions.
• Hojo (補助) / Assistance: For people who need help with some important decisions but generally manage daily life. The assistant (hojonin / 補助人) provides consent or representation only for specific matters designated by the court. This is the lightest level of guardianship.

The family court decides which level is appropriate based on a medical evaluation and the circumstances of the case.

What Does a Guardian Actually Do?

A guardian’s role falls into two categories:

• Zaisankanri (財産管理) / Property management: Managing bank accounts, paying bills, handling the disability pension, managing savings and other assets, processing inheritance procedures, filing tax returns, and protecting assets from misuse.
• Shinjou hogo (身上保護) / Personal welfare: Signing contracts for welfare services, arranging group home placement, entering into care agreements, and ensuring the person’s living situation is appropriate.

Important things a guardian does NOT do:

• A guardian does not make medical decisions such as consenting to surgery on the person’s behalf.
• A guardian does not provide hands-on daily care, cooking, cleaning, or personal support.
• A guardian does not decide where the person lives against their will (the person’s wishes must be respected).

The guardian’s role is legal and administrative. They are not a caregiver.

Can a Parent Stay Involved?

Yes. There are several ways parents can remain central to their child’s guardianship, even if a professional is involved.

Parent as Guardian

A parent can be appointed as the guardian. You name yourself as the candidate when you apply. However, the court may not approve this, especially if the person has significant assets or if the court has concerns about the arrangement. If a parent is appointed, they may serve without compensation (family guardians often do not request fees).

Multiple Guardians with Divided Roles

The family court can appoint more than one guardian, each with different responsibilities. For example, a parent could be appointed as the guardian for personal welfare (shinjou hogo), handling care arrangements and daily living decisions, while a professional (lawyer or judicial scrivener) is appointed as the guardian for property management (zaisankanri), handling finances and legal matters. This allows the parent to stay closely involved in their child’s life while ensuring professional financial oversight.

Guardian Supervisor (Kouken Kantoku Nin / 後見監督人)

The court can appoint a guardian supervisor (kouken kantoku nin / 後見監督人) to oversee the guardian’s work. If a family member is the guardian, the court may appoint a professional as the supervisor to provide oversight. If a professional is the guardian, a parent could potentially be involved through other channels, such as regular communication with the guardian and participation in the service planning process.

The supervisor reviews the guardian’s reports, ensures the person’s assets are being managed properly, and can take action if the guardian is not performing their duties correctly.

How to Apply Through the Family Court

Applications for statutory guardianship are filed with the family court that has jurisdiction over the person’s place of residence (based on their juuminhyou / 住民票 address).

Who Can Apply?

• The person themselves
• The person’s spouse
• A relative within the fourth degree (parents, siblings, grandparents, aunts, uncles, etc.)
• A prosecutor
• The mayor of the person’s municipality

What Documents Do You Need?

• Moushitate sho (申立書): The application form, available from your local family court or downloadable from the courts.go.jp website.
• Shindan sho (診断書): A medical certificate describing the person’s mental or cognitive condition, completed by a doctor on the court’s designated form.
• Koseki touhon (戸籍謄本): The person’s family register.
• Juuminhyou (住民票): The person’s residence certificate.
• Touki sareteinai koto no shoumei sho (登記されていないことの証明書): A certificate confirming that no existing guardianship is registered for this person. Available from the Legal Affairs Bureau (houmukyoku / 法務局).
• Moushitate jijou setsumeisho (申立事情説明書): A statement explaining the circumstances of the application: why guardianship is needed, what the person’s daily life looks like, and who the proposed guardian is.
• Financial documents: A list of the person’s assets, income, expenses, bank statements, and other financial information.
• Shin’in kankei zu (親族関係図): A family relationship diagram.

The Application Process

• Step 1: Get the application forms from the family court or download them. Each family court may have slightly different forms, so check with your specific court. Many family courts offer a procedure guidance session (tetsuzuki annai / 手続案内) where staff explain the process and documents needed.
• Step 2: Have the doctor complete the medical certificate on the court’s designated form.
• Step 3: Gather all supporting documents.
• Step 4: Submit the application (moushitate / 申立て) to the family court, either in person or by mail.
• Step 5: The court reviews the application, interviews the applicant and the person, and may interview other family members and the proposed guardian candidate.
• Step 6: The court may order a formal medical evaluation (kantei / 鑑定) if the initial medical certificate is not sufficient. This costs money (see fees below) and adds time.
• Step 7: The court issues its decision (shinpan / 審判), appointing a guardian and specifying their authority. The guardian is then registered with the Legal Affairs Bureau.

The process typically takes one to four months from filing to decision.

Important: Once you file the application, you cannot withdraw it without the court’s permission. And the court may appoint a different guardian than the candidate you named. Consider these facts carefully before filing.

Application forms and guides: Courts of Japan: Guardianship Application

How Much Does It Cost?

Application Costs

The one-time costs of filing the application are relatively modest. They include a filing fee, a registration fee, postage, document fees, and possibly a medical evaluation fee if the court orders one. The application fees are paid through revenue stamps (shuunyuu inshi / 収入印紙).

For current application fee amounts: Courts of Japan: Guardianship Procedure

Ongoing Guardian Fees

This is the cost that concerns parents most. If a professional guardian is appointed, they receive ongoing compensation (houshuu / 報酬) from the person’s assets. The amount is not fixed by law. The guardian requests compensation from the family court, and the court determines the amount based on the complexity of the work and the person’s financial situation.

The Tokyo Family Court publishes a guideline (“Seinen Koukenin Tou no Houshuu Gaku no Meyasu” / 成年後見人等の報酬額のめやす) that is widely used as a reference nationwide. This guideline sets basic monthly compensation ranges based on the amount of managed assets. Other family courts may follow similar or different guidelines. Contact your local family court for the fee standards that apply in your jurisdiction.

If a guardian supervisor is also appointed, the supervisor also receives compensation from the person’s assets, adding to the total cost.

Family guardians (parents, siblings, relatives) often serve without requesting compensation. If they do request it, the court sets a lower amount than for professional guardians.

The lifetime cost: For a young adult with a disability who receives guardianship at age 18 or 20, the guardian fees could continue for 50 or 60 years. Even at a modest monthly fee, this adds up to a very significant amount over a lifetime. This is one of the most important factors for parents to consider.

For current fee guidelines: Tokyo Family Court: Guardian Fee Guidelines (PDF)

Fee Subsidies

For people with limited income and assets, many municipalities offer a seinen kouken seido riyou shien jigyou (成年後見制度利用支援事業), a guardianship fee subsidy program that can help cover guardian fees and application costs. Ask at the shougai fukushi ka at your ward office.

For people who cannot afford the legal costs of applying, Houterasu / 法テラス (the Japan Legal Support Center) offers free legal aid services, including assistance with guardianship applications. Their national call center number is 0570-078374. Houterasu website

Alternatives to Full Guardianship

Before deciding on guardianship, it is worth knowing that there are other ways to protect your child’s finances and legal interests. Many families find that one of these alternatives provides the support they need without the concerns that come with full guardianship.

• Hojo (補助 / Assistance): The lightest level of statutory guardianship. The court authorizes the assistant to help with only specific, designated matters. The person retains independence for everything else. This may be enough if your child can manage daily life but needs help with major financial decisions.
• Hosa (保佐 / Curatorship): A middle level where the curator must consent to certain important actions (borrowing, selling property, etc.) but the person retains more independence than under full guardianship.
• Nichijou Seikatsu Jiritsu Shien Jigyou (日常生活自立支援事業) / Daily Life Independence Support Program: A social welfare program (not a guardianship system) that helps people with disabilities manage everyday financial tasks like paying bills, withdrawing money, and managing important documents. A support worker visits regularly to assist. This can be used without guardianship and is administered through the local shakai fukushi kyougikai (社会福祉協議会), the social welfare council.
• Tokutei Zouyo Shintaku (特定贈与信託) / Special Needs Trust: For managing large assets, a trust bank can hold and manage the money professionally without the need for a guardian. The trust makes regular payments for the person’s living expenses. See our article “Special Needs Trusts in Japan.”
• Kouken Seido Shien Shintaku (後見制度支援信託) / Guardianship Support Trust: Even within the guardianship system, if the person has significant assets, the court can place those assets in a trust at a bank, where they are protected. The guardian handles day-to-day finances, but the bulk of the assets are safely held by the bank and cannot be touched without court approval.

The 2026 Civil Code Reform

On April 3, 2026, the Japanese government approved a major reform bill and submitted it to the Diet. If passed, this will be the most significant change to the guardianship system since it began in 2000. Implementation is estimated at approximately two and a half years after enactment.

Key changes:

• Unification of the three types: Kouken, hosa, and hojo will be consolidated into a single “hojo” system. This is intended to reduce the broad authority that full guardianship currently grants and to better respect the person’s own decision-making ability.
• End of the lifetime requirement: The reform will allow guardianship to be ended when it is no longer needed, even if the person’s capacity has not recovered. This enables time-limited, purpose-specific use of the system.
• More individualized support: The court will tailor the guardian’s authority to match the individual’s actual needs, rather than applying a broad category.

These changes address several of the most serious concerns parents have about the current system. Follow the progress through the Ministry of Justice.

MOJ reform page: Reform of Adult Guardianship System

Practical Tips

• Do not rush into guardianship. Take time to understand the system, talk to professionals, and consider whether it is truly necessary for your family’s situation.
• Get a free consultation first. Visit your nearest kenri yougo shien no chuukaku kikan (権利擁護支援の中核機関), rights advocacy support center, for free guidance. Find yours through the MHLW guardianship consultation page.
• Consider the lighter options first. Hojo (assistance) or hosa (curatorship) may provide the protection your child needs without the full restrictions of kouken (full guardianship).
• If you want a family member to be the guardian, name them as the candidate and prepare a clear explanation for the court of why they are the best choice. Be aware that the court may still appoint a professional, especially if the person has significant assets.
• Ask about dividing the guardian role. A parent for personal welfare, a professional for finances. This lets you stay close to your child’s daily life while ensuring professional financial management.
• The application process is in Japanese and involves legal paperwork. Consider hiring a judicial scrivener (shihou shoshi / 司法書士) or lawyer (bengoshi / 弁護士) to assist with the filing, especially if you are not comfortable with legal Japanese.
• Visit the family court for a procedure guidance session (tetsuzuki annai) before filing. Staff will walk you through the process and the required documents specific to your court.
• Ask your municipality about the guardianship fee subsidy (seinen kouken seido riyou shien jigyou) if the person has limited assets.
• Talk to other parents. Organizations and parent groups that focus on disability and oyanaki ato planning can share firsthand experience about guardianship.
• Follow the 2026 reform. The changes will make the system significantly more flexible. If your child is still young, the reformed system may be in place by the time you need it.
• Guardianship is just one tool. It works alongside other tools like the special needs trust, the mutual aid insurance system, and group home placement. See our article “Planning for Life After You’re Gone” for how these pieces fit together.

Key Terms

Japanese Term	English
Seinen kouken seido / 成年後見制度	Adult guardianship system
Nin’i kouken / 任意後見	Voluntary guardianship
Houtei kouken / 法定後見	Statutory guardianship
Seinen koukenin / 成年後見人	Adult guardian (full)
Hosanin / 保佐人	Curator
Hojonin / 補助人	Assistant
Kouken kantoku nin / 後見監督人	Guardian supervisor
Katei saibansho / 家庭裁判所	Family court
Moushitate / 申立て	Application (to the court)
Shinpan / 審判	Court decision
Kantei / 鑑定	Formal medical evaluation
Houshuu / 報酬	Guardian compensation
Zaisankanri / 財産管理	Property management
Shinjou hogo / 身上保護	Personal welfare protection
Houterasu / 法テラス	Japan Legal Support Center
Shakai fukushi kyougikai / 社会福祉協議会	Social welfare council

Useful Resources

MHLW: Guardianship Quick Guide (成年後見はやわかり): https://guardianship.mhlw.go.jp/

MHLW: Types of Guardianship (成年後見制度の種類): https://guardianship.mhlw.go.jp/personal/type/

MHLW: Statutory Guardianship (法定後見制度とは):

https://guardianship.mhlw.go.jp/personal/type/legal_guardianship/

MHLW: Voluntary Guardianship (任意後見制度とは):

https://guardianship.mhlw.go.jp/personal/type/optional_guardianship/

MHLW: Guardianship Consultation Windows (相談窓口): https://guardianship.mhlw.go.jp/consultation/

Courts of Japan: Guardianship Application (成年後見等申立て): https://www.courts.go.jp/saiban/syurui/syurui_kazi/kazi_06_01/index.html

Tokyo Family Court: Guardian Fee Guidelines (報酬額のめやす, PDF): https://www.courts.go.jp/tokyo-f/vc-files/tokyo-f/file/H3103zinpangakumeyasu.pdf

MOJ: Reform of Adult Guardianship System (成年後見制度の見直し): https://www.moj.go.jp/shingi1/housei02_003007_00008

Houterasu (Japan Legal Support Center): https://www.houterasu.or.jp/