Information Asymmetry in Japan's Traditional Townhouse Market — Connecting Individual Purchase to Public Asset Activation

FIRST-HAND Local's field report published on 27 April 2026 — titled "Renovation needs only surface after purchase: information asymmetry in the kominka market and the invisible debt that migrants carry" — documents the experience of a woman in her thirties (originally from Amagasaki, Hyogo Prefecture) and her husband, who purchased a traditional Japanese house in the mountainous region of Nara Prefecture and relocated there. The husband had previously worked at a furniture manufacturer and brought substantial construction knowledge; together the couple represented an unusually well-equipped buyer profile. Even so, a series of unforeseen costs surfaced after the purchase. That gap is the analytical core of the FHL piece.

This article takes the FHL report as its starting point. The aim is to organize the information asymmetry of the kominka market as a structure, and to re-read it through the lens of public asset activation — closed schools, former offices, former government buildings, municipally-owned kominka, and the broader akiya (vacant house) policy field. While the sister article

addresses the B2B view of "municipal ownership plus private operation," the present article centers on the information asymmetry that individual buyers and relocating migrants face — a B2C view — and connects that to public asset activation.

Five Categories of Unforeseen Cost in the FHL Case

The FHL report frames these not as bad luck on individual properties but as structural information asymmetry in the kominka market. The relevant variables — soil environment, water cycle, humidity, local microclimate — fall outside both the Important Matters Explanation required under the Real Estate Brokerage Act and the standard scope of existing housing condition inspections. Sellers respond to direct questions but rarely volunteer information, and municipal migration support windows focus on subsidy referrals and lifestyle promotion, leaving the practical work of contract negotiation, registry, and renovation planning largely unsupported.

The Gap Between Vacant House Stock and Formal Market Flow

A record 9.0 million vacant houses and a record-high 13.8% vacancy rate. Excluding rentals, properties for sale, and secondary residences, vacant houses still total 3.85 million — 5.9% of all housing stock. Against that backdrop, participating municipalities 1,030 / 1,788 (58%), 14,248 listed properties, cumulative deals approximately 16,500. If the denominator is restricted to vacant houses excluding rentals, sales properties, and secondary residences (3.85 million), bank listings account for roughly 0.4%. The FHL editors' field intuition that "registered listings are about one-tenth of actual vacant houses" turns out to be, if anything, a conservative figure.

Properties that make it onto the bank have passed three filters: clear intention to sell, completed registry of inheritance, and willingness to register with the municipality. The dominant trading channel remains private networks and relational transactions. The structural question this article raises is how to design that "ninety-percent plus" of off-registry transactions.

The Range of Kominka Renovation Costs

A tenfold range can rarely be narrowed at the pre-purchase estimation stage. That is the defining economic feature of the kominka market. Because price formation does not function properly, buyers end up confirming costs only after purchase.

The reason kominka renovation costs resist advance confirmation traces back to a structural fact: each assessment item carries risk profiles that differ from contemporary housing.

Structural Frame and Traditional Construction

In wooden kominka over fifty years old, contemporary conventional construction methods often coexist with traditional construction methods — stone-base footings (ishibadate), traditional joinery, and shaft connections. At the point of brokerage contract signing, 18% of clients request inspection mediation. Implementation rates run at 88% on the seller side and 6% on the buyer side. A separate 2019 study in Toyama Prefecture found a 5.18% implementation rate for secondhand detached houses. The low uptake itself is a problem, but the more structural limit lies in the fact that the inspection scope is built around the deterioration profile of contemporary housing. Settlement of stone-base footings, joinery deterioration in traditional connections, and moisture content in earthen walls fall outside the inspection scope.

Leakage, Plumbing, and Water Infrastructure

Leakage in old buildings is rarely confined to the roof surface — it tends to compound with eave moisture, attic condensation, and within-wall condensation. Plumbing may retain lead or cast-iron pipes, and for properties that rely on well water, seasonal variations in the local groundwater system directly affect daily life (the two-month well depletion documented in the FHL case is a textbook example). These conditions are difficult to detect through inspections built around "visual and instrumental" assessment, and in practice the effective safeguard is hearing-based input from specialists with locally specific hydrological knowledge.

Seismic and Insulation Assessment

A private-sector certification that conducts a 519-item survey of wooden houses over 50 years old, producing a 30-year preventive maintenance plan and a building history record. Three-year renewal cycle. The certification is not a national qualification, but it functions as a private complement to the standard inspection regime, specializing in traditional construction and kominka. On insulation, the design knowledge required to preserve the natural ventilation performance of traditional construction while securing contemporary thermal comfort generally exceeds the standard scope of mainstream renovation contractors.

The information asymmetry of the kominka market is best read not as a single institutional gap but as three layered structures.

Physical Layer — Domains the Existing Regime Cannot Measure

Soil environment, water cycle, humidity, local microclimate, deterioration assessment for traditional construction. Information asymmetry in the existing housing market is structured across the three-party relationship of sellers, buyers, and brokers, and cannot be resolved by the inspection regime alone — this point has been raised in the academic literature. In the kominka case, a fourth variable — locally specific physical environment — is added to that three-party structure, deepening the asymmetry.

Transaction Layer — Relational and Off-Registry Trades Dominate

Bank-listed properties account for roughly 0.4% of the underlying stock; the remaining ninety-plus percent moves through relational and private transactions. Information about properties circulates inside local real estate offices, migration consultants, and neighbor networks. By the time an outside buyer accesses a property, a degree of screening has already occurred — properties that reach the open market often signal "no one else is interested, which may itself indicate a defect."

Support Layer — Gaps in Municipal Migration Support

Municipal migration support windows focus on subsidy referrals and lifestyle promotion. Practical support — contract negotiation, registry work, renovation cost estimation, contractor selection — typically falls outside the standard scope of these windows. The amendment introduced the new category of Managed-Insufficiently Vacant House, the removal of the residential-land special tax treatment, the new Vacant House Management and Activation Support Corporation framework, and Vacant House Activation Promotion Zones with relaxed access road and use restrictions. Through this amendment, municipalities can now designate NPOs and incorporated associations as support corporations. The framework is in place, but it is still early in deployment, and concrete cases functioning as accompanying support services for individual buyers remain limited.

This is where the core question of this article comes into focus. The information asymmetry facing individual buyers and the activation challenge for municipally-owned kominka may share the same root cause: the absence of an underlying information infrastructure in the kominka market.

Connection 1 — Municipal-Led Ex-Ante Evaluation as a Public Stock

A possible design embeds kominka appraisal — or equivalent inspection — into vacant house bank registration, treating renovation cost estimation and risk disclosure as part of the listing record. For buyers, this raises transparency at the decision stage. For municipalities, it suppresses post-transaction complaints and the administrative resource burden that follows them. The cost need not be borne by municipalities alone; matching with a buyer-side application deposit, or leveraging the new Vacant House Management and Activation Support Corporation framework for cost sharing, is realistic.

Connection 2 — Area-Based Redevelopment with Closed Schools and Former Offices

Closed schools, former offices, and former government buildings tend to sit at historically central locations and are often surrounded by clusters of kominka. In the MLIT Small Concession Formation Support Program, four of seven FY2025 selections targeted kominka. Extending the "area-based activation" perspective of that program — designing a single scheme that bundles one closed school with five to ten adjacent kominka — opens space to resolve property-level information asymmetry through "area-unit ex-ante evaluation."

Connection 3 — Renovation Plan, Deposit, and Completion Obligation (Italian Model)

Italy's One-Euro House program sells abandoned houses for one euro in exchange for (i) a renovation plan submitted within twelve months, (ii) a deposit of 3,000 to 10,000 euros (refunded on completion), and (iii) a completion obligation typically set at two to three years. The actual renovation investment to reach contemporary livability runs from 20,000 to 30,000 euros for smaller properties and 50,000 to 100,000 euros for larger or more complex homes. In contrast to Japan's vacant house bank model, which stops at "matching," the Italian model writes the renovation plan and deposit into the contract stage, suppressing the surprise-cost problem before purchase.

The UK's Historic England maintains grant schemes for Listed Buildings (Grade II and above) and for properties of historic value within Conservation Areas, covering repair, preservation, and emergency safeguarding of empty buildings. The design — daily maintenance excluded, structural conservation strongly supported — parallels Japan's Registered Tangible Cultural Property system, but Listed Buildings use an explicit grade system that delineates eligibility more clearly than the Japanese counterpart.

Three implications follow from the structural reading above.

Implication 1 — The Kominka Market Problem Is Information Infrastructure, Not Property Matching

So long as buyers, sellers, brokers, and municipalities do not share a common information infrastructure, raising the number of property matches will not resolve the information asymmetry. Growing the listing count on the vacant house bank — a quantitative expansion — sits on a different layer from the qualitative buildout of information infrastructure.

Implication 2 — Public Asset Activation Tools Can Be Repurposed for Individual Buyer Support

Small Concession schemes for municipally-owned kominka, area-based activation pairing closed schools with kominka clusters, and the Vacant House Management and Activation Support Corporation framework are all being built out as public-sector instruments. Repurposing these as "information infrastructure that individual buyers can access" looks feasible within the current institutional perimeter.

Implication 3 — Shopping Refugees, Vacant Houses, and Public Asset Activation Are Different Cross-Sections of the Same Problem

At the policy layer, the shopping refugee problem, vacant house policy, and public asset activation are managed by different agencies under different budget lines. On the ground in shrinking communities, however, they all converge on a single underlying question — the cost of maintaining physical space in regions with declining population. Re-reading the information asymmetry of the kominka market as the intersection of these three policy frames opens hints for institutional design that crosses agency boundaries.

Open Questions for Municipalities, Private Operators, and ISVD

• For municipal staff: Can vacant house bank registration include a kominka appraisal as a standard component? Can area-based redevelopment schemes be designed that pair adjacent closed schools and former offices with surrounding kominka clusters?
• For private operators: Does a "kominka inspection plus renovation plan" service model that serves both individual buyers and municipal Small Concession projects make business sense? What is the role of an aggregator that knits together kominka appraisers, architects, and local contractors?
• For ISVD and Correlate Design: Within the production work of public asset activation, the buildout of information infrastructure for the kominka market falls inside scope. Integrating the B2B view of the sister article (municipally-owned kominka) with the B2C view developed here (individual buyers) into a single business design is a question we want to leave open for the next phase of work.

ISVD provides scheme design consultation and specialist referrals — free of charge — to municipalities and community organizations that hold kominka assets. The organization also welcomes inquiries from municipalities and private operators interested in building information infrastructure for individual buyers.

Traditional Townhouses and Small Concessions

A B2B-focused structural analysis of why four of seven FY2025 Small Concession Formation Support Program selections involve kominka

The MLIT Small Concession Guidebook (May 2026)

A practical reading of the MLIT guidebook on activating idle public facilities

A Framework for Activating Idle Public Real Estate

Activation patterns and institutional design for closed schools, former government buildings, former offices, and public housing

References

2023 Housing and Land Survey (2024)

Amendment to the Special Measures Act on Vacant Houses (Act No. 50 of 2023) (2023)

Overview of the Existing Housing Condition Inspection Regime (2018)

National Akiya/Land Bank (2024)

Registered Tangible Cultural Properties (Buildings) System (2025)

Information Asymmetry in the Existing Housing Market and Countermeasures (2017)

Renovation needs only surface after purchase: information asymmetry in the kominka market and the invisible debt that migrants carry (2026)