Japan Contract Non-Conformity in 2026: What Used-Home Buyers Should Check

If you discover a problem after buying a used home in Japan, the first question is not simply “is this a defect?” It is whether the property delivered to you was in conformity with the purchase contract. Japan calls this 契約不適合 (keiyaku futekigō), or contract non-conformity.

That distinction matters because an old house can have wear without breaching the contract, while a condition described as absent—such as “no rain leakage”—can become a much stronger issue if evidence shows it already existed at handover. The buyer's safest workflow is therefore contract → evidence at handover → seller status → notice/action, not defect → assumption of compensation.

The short answer: what can a buyer ask for?

Japan's Civil Code framework for a non-conforming sale can include remedies such as completion or repair, a price reduction, damages, or cancellation depending on the facts and legal requirements. But those remedies do not arise merely because a buyer dislikes the condition after closing.

The Tokyo Metropolitan Government's official real-estate transaction guide gives a useful used-home example: if a home was sold on the basis that there was no rain leakage but rain leakage existed, that can be a quality non-conformity. By contrast, ordinary deterioration from age is generally part of the quality expected of an existing home unless the contract says otherwise. A problem caused only after handover is also a different case.

For buyers, the practical lesson is simple:

Write the important condition into the deal, preserve evidence at handover, and notify the seller promptly if reality does not match the agreement.

1. Start with the contract, not the repair estimate

A contractor may correctly tell you that a roof, pipe or foundation needs work. That establishes a physical condition; it does not by itself establish what the seller legally promised.

Pull together:

• the sale contract and all special clauses;
• the property condition report or seller disclosure;
• the Important Matters Explanation;
• inspection or building-condition survey material;
• repair invoices, photographs and messages provided before signing;
• handover records and photographs.

Then ask: what statement or agreed condition does the discovered problem contradict?

Examples:

This is why Engawa's Important Matters Explanation guide and home inspection guide solve different problems from this article. Disclosure and inspection help establish facts before signing; contract non-conformity governs what happens when the delivered property does not match the agreement.

2. Separate old-house wear from a broken promise

Used homes are not new homes with a discount. Age, deferred maintenance and finite equipment life are part of the buying decision.

Tokyo's official transaction guide specifically distinguishes normal age-related decline from a contract non-conformity. So a 25-year-old component reaching the end of its service life is not automatically evidence that the seller breached the sale contract.

The buyer should classify a post-closing discovery into one of four buckets:

1. Clearly promised condition — the contract or disclosure says the condition was absent, fixed or at a specified standard.
2. Known and accepted condition — the issue was disclosed or expressly factored into the deal.
3. Ordinary age/maintenance risk — deterioration consistent with the existing-home condition and no contrary promise.
4. Unclear — documents conflict or do not say enough; preserve evidence and obtain professional interpretation before making assumptions.

The fourth bucket is common. Treat it as an evidence problem, not as an invitation to overstate a legal position.

3. Identify who actually sold the property

Do not confuse the broker with the seller.

A licensed real-estate business may broker a private owner's sale, or it may buy, renovate and resell a property itself. Those situations are legally different.

When a licensed real-estate business is itself the seller, Article 40 of Japan's Real Estate Brokerage Act restricts certain provisions that would make the buyer worse off than the Civil Code rule for type or quality non-conformity. In particular, the statute allows a special notice period based on handover only when it is at least two years; a conflicting buyer-disadvantageous clause is void under the provision.

That does not mean every professional-seller dispute is automatically covered or that every remedy lasts exactly two years. It means seller status is a crucial input before you interpret a waiver, short notice period or responsibility clause.

For a private-to-private used-home sale, contractual limitations can play a much larger role. Have a Japanese lawyer review a material clause rather than relying on a generic internet summary.

4. Know the Civil Code's one-year notice trigger

For a type or quality non-conformity, Civil Code Article 566 states that the buyer generally must notify the seller within one year after the buyer learns of the non-conformity to preserve the listed remedies. The article contains an exception when the seller knew of the non-conformity at handover or failed to know of it through gross negligence.

Two cautions are important:

• this statutory rule is not the only time issue that can matter in a real dispute; and
• the contract and seller's legal status may change how the practical deadline analysis works.

Therefore, do not use “one year” as permission to wait. Notify promptly in writing, describe the condition without exaggeration, preserve the evidence, and avoid destructive repairs before the seller or an expert has had a fair chance to inspect unless urgent work is necessary to prevent further damage.

5. Build an evidence packet before the site changes

The strongest post-closing file is chronological.

Create one folder containing:

• date and time the problem was first noticed;
• photos and video before repair or demolition;
• weather conditions if relevant to a leak;
• inspection report and pre-purchase photos;
• seller disclosures and repair history;
• the exact contract provisions you think matter;
• contractor or engineer findings, separating observation from opinion;
• copies of every notice sent to the seller or broker;
• invoices for urgent mitigation.

If water is actively entering the house, for example, preventing additional damage can be more important than preserving a perfect forensic scene. Photograph first when safe, document why emergency work was required, keep removed materials where practical, and ask the contractor to record what was observed before work began.

6. Do not make the inspection carry a legal burden it cannot carry

A pre-purchase building-condition survey is highly useful, but MLIT's inspection framework is about observed deterioration and specified building elements; an inspection is not a universal guarantee that no hidden problem exists.

That creates two separate buyer questions:

• Condition question: what did the inspector observe and what was outside scope?
• Contract question: what did the seller agree the buyer would receive?

A clean inspection can help evidence, but it does not automatically make a later problem the inspector's or seller's liability. Likewise, an inspection recommendation to investigate further should not disappear from the decision file just because the sale contract was signed.

7. Worked example: rain leakage two weeks after closing

Assume a buyer completes on a 30-year-old detached house. Two weeks later, heavy rain produces a ceiling stain.

The wrong workflow is:

1. call a roofer;
2. receive a ¥700,000 estimate;
3. demand ¥700,000 from the seller because “hidden defects are covered.”

A stronger workflow is:

1. Stop further damage and photograph the condition.
2. Read the contract and disclosure. Did they say no rain leakage, disclose a previous leak, or limit responsibility for specified components?
3. Check pre-closing evidence. Inspection photos, repair invoices and messages may show whether the condition likely existed at handover.
4. Identify seller status. Private owner or licensed real-estate business selling its own inventory?
5. Send prompt written notice describing what was found and requesting inspection/response without prematurely asserting facts you cannot prove.
6. Obtain technical evidence on likely cause and age of the condition.
7. Get legal advice before agreeing to a final release, major destructive work or a disputed settlement.

The repair price matters, but it comes after establishing the contractual and factual basis of the claim.

8. Five clauses to highlight before you sign a used-home contract

Before signing, mark these provisions and translate them accurately if necessary:

• Condition statements: what is expressly represented about leakage, termites, structure, plumbing or equipment?
• Known defects/disclosures: what are you accepting with knowledge?
• Responsibility limitations: which categories are limited or excluded, and does seller status affect enforceability?
• Notice procedure and period: where, how and by when must notice be sent?
• Inspection/handover mechanics: what evidence will document condition at delivery?

If the contract uses a broad “as-is” concept, do not reduce the analysis to the English phrase. The Japanese wording, disclosures, seller status and mandatory law matter.

Buyer decision checklist

Before closing:

• I know whether the seller is a private owner or a licensed real-estate business selling its own property.
• I have read the responsibility/limitation clauses, not just the price and handover date.
• Material condition promises are written, not only verbal.
• Known defects and accepted exclusions are specific enough to understand.
• I have inspection and handover evidence for the condition that matters most.
• I know where written post-closing notice must be sent.

After discovering a problem:

• Prevent additional damage where necessary.
• Photograph/video before the condition changes.
• Compare the issue with the contract and disclosures.
• Notify the seller promptly in writing.
• Preserve technical evidence and repair records.
• Use qualified Japanese legal advice for a material or disputed claim.

Sources

• Tokyo Metropolitan Government — Real Estate Transaction Guide: problems and defects found after handover
• e-Gov Laws — Civil Code (see Articles 562–566)
• e-Gov Laws — Real Estate Brokerage Act (see Article 40)
• MLIT — existing-home building condition survey / inspection information

Sources checked 6 September 2026. This article is general buyer information, not legal advice. Contract wording, seller status, facts at handover, limitation provisions, limitation periods and available remedies can materially change the analysis. For a significant post-closing problem, preserve evidence and consult a qualified Japanese lawyer before relying on a general summary.

Frequently asked questions

What is contract non-conformity when buying a home in Japan?+

Contract non-conformity (契約不適合) means the property delivered does not conform to the contract in type, quality or quantity. For a used home, the decisive question is therefore what the contract says the buyer was entitled to receive, not whether the home is simply old or imperfect.

Does every defect found after closing make the seller liable?+

No. Normal age-related deterioration, a condition that the contract accepted, or damage caused only after handover is not automatically a contract non-conformity. The facts at handover and the contract wording need to be compared.

How quickly should a buyer report a hidden defect in Japan?+

Act promptly. Civil Code Article 566 provides a one-year notice rule from when the buyer learns of a type or quality non-conformity, subject to its statutory exception. Contracts can also contain important allocation and notice provisions, and special buyer-protection rules can apply when a licensed real-estate business is itself the seller.

Is a home inspection the same as contract non-conformity protection?+

No. An inspection is evidence about condition at a point in time; contract non-conformity is a legal and contractual question about whether the delivered property matched the agreement. A good inspection can reduce uncertainty and document conditions, but it does not replace careful contract drafting or legal advice.

Why does it matter whether the seller is a private owner or a real-estate company?+

Because Japan's Real Estate Brokerage Act restricts certain buyer-disadvantageous provisions when a licensed real-estate business sells its own property. Private-to-private sales can have a different contractual risk allocation, so identify the seller's legal status before treating a short liability clause as routine.

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