Most foreign buyers in Japan do one of two things:

• They buy what feels right — photos, location name, price point.
• They buy what yields right — a gross yield number on a listing page.

Neither is underwriting.

At Nippon Tradings International, the difference between a good purchase and a quietly bad one usually comes down to whether you model the deal like an operator — including vacancy, capex, fees, and exit logic — instead of treating the listing price as the final decision.

This guide gives you a practical, reusable underwriting framework for:

• Condo units
• Small multi-unit buildings (apato)
• Detached homes (ikkodate)

The model is durable and asset-type-agnostic. The numbers cited reflect current Japanese market conditions.

1. The Only Return Metric That Matters: Real Net, Not Headline Yield

Gross rental yields in Japan averaged approximately 4.2% nationwide as of early 2025 — and that is before costs. In Tokyo’s strongest micro-locations, net yields after fees and taxes compress significantly further. Gross yield is marketing. Net performance is reality.

To properly underwrite a Japan deal, you need four things:

• Income assumptions you can defend — based on comparable rents, not asking price
• Cost assumptions you won’t regret — management fees, taxes, insurance, common area costs
• A capex reserve you can survive — not optional, not a footnote
• An exit story you believe — who buys this next, and at what cap rate

2. The Deal Model: A Simple Template

Use this structure across all asset types. Inputs change; the framework does not.

A) Income

• Scheduled gross rent (fully occupied)
• Vacancy deduction (see asset-specific assumptions below)
• Other income: parking, storage, signboard rights

B) Operating Costs

• Property management fees: typically 5–10% of monthly rent, with the industry standard around 5%; some full-service managers charge up to 8%
• Common area maintenance (apato and managed condos)
• Baseline repairs and maintenance
• Fire and earthquake insurance
• Fixed asset tax (固定資産税): 1.4% of assessed value annually (note: assessed value is typically 50–70% of market value for land, 60–70% for buildings); city planning tax (都市計画税) adds up to 0.3% in designated urban zones
• Utilities you cover, if any

C) Capital Expenditure Reserve (Capex)

This is not “repairs.” This is replacing things that wear out on a cycle — roofs, plumbing stacks, exterior sealing, water heaters. It must be budgeted, not discovered.

D) Net Operating Income (NOI)

Income minus all operating costs — not including loan payments. This is your pre-financing performance number.

E) Stress Test

What happens when vacancy rises or a major repair lands in the same year? Model it explicitly.

F) Exit Logic

Who buys this asset next — and at what yield expectation? Note that capital gains tax in Japan is 39.63% for properties held five years or less, and 20.315% for properties held longer than five years. Holding period dramatically affects net exit proceeds.

3. Underwriting Condos (Unit in a Managed Building)

Condos are not capex-heavy in the same way as a whole building — but they are fee and governance heavy. You are buying into a collective ownership structure, and the health of that structure matters as much as the unit itself.

Condo-Specific Inputs

• Monthly management fee (管理費) — covers common area upkeep; typically ¥5,000–¥15,000/month depending on building grade and facilities
• Monthly reserve fund contribution (修繕積立金) — check if the reserve is adequately funded relative to the building’s repair plan
• Special assessment risk — review the long-term repair plan (長期修繕計画) and assess how close major works are
• Renovation constraints — many buildings restrict interior changes, which affects rentability and resale buyer pool
• Building age and seismic compliance — buildings constructed after 1981 meet the New Seismic Standard (新耐震基準); those built after 2000 meet enhanced standards

Vacancy Assumptions

• Strong station areas in Tokyo’s 23 wards: vacancy below 3–4% in central wards (Chiyoda, Shibuya consistently under 3%)
• Regional cities: Osaka ~3.8%, Nagoya ~3.9%, Fukuoka ~5.3%, Sendai ~5.9%
• Weaker micro-locations or aging buildings with low tenant appeal: budget 8–12%

Capex Reserve

Lower than a whole building, but never zero:

• Interior refurbishment between tenants (flooring, walls, lighting): typically ¥300,000–¥700,000 per cycle
• Appliances: air conditioner units (¥80,000–¥150,000 per unit), water heaters (¥100,000–¥200,000)

Exit Logic

Condos have the broadest resale pool — they attract both investors and end-users. However, a weak building reserve fund or an impending special assessment can destroy the value of an otherwise solid unit. Always request the management association’s financial statements before purchase.

NTI Rule: A weak building can destroy an otherwise good unit. The condo association’s balance sheet is part of your underwriting.

4. Underwriting Apato Buildings (Small Multi-Unit)

An apato is a business, not a single unit. The most common mistake is assuming stability based on a rent roll snapshot taken at the point of sale. Tenants turn over. Units sit vacant. Buildings age. Model the reality, not the brochure.

Apato-Specific Inputs

• Vacancy and turnover per unit type — studios, 1K, 1LDK have very different demand profiles
• Leasing costs per turnover: advertising (AD fees, often 1–2 months’ rent paid to agents), unit cleaning (¥30,000–¥80,000), and minor refurbishment
• Management company quality — time-to-lease and responsiveness directly affect NOI
• Common area maintenance: exterior lighting, shared corridors, parking areas
• Compliance and safety upgrades depending on building age — fire equipment, handrail standards, and electrical capacity
• Documented repair history — if the seller cannot provide it, assume deferred maintenance

Vacancy Assumptions

Be conservative. The right number depends on:

• Unit mix — tiny studio units (under 20 sqm) face growing regulatory scrutiny and limited demand in some municipalities
• Local demand driver — proximity to a university, hospital, or major employer cluster materially reduces vacancy risk
• Building condition and visual appeal relative to competing stock

A reasonable baseline for regional city apato is 8–15% vacancy. In strong urban micro-locations with verified demand, 5% may be defensible. Never underwrite to 0%.

Capex Reserve

This is mandatory. Budget for replacement cycles on:

• Roof: replacement every 20–30 years, typically ¥1.5M–¥4M+ depending on size and material
• Exterior walls and sealing: repainting and caulk replacement every 10–15 years
• Corridors, stairs, and railings: corrosion and safety compliance
• Plumbing stacks and drainage: expensive and disruptive; non-negotiable in older buildings
• Electrical capacity: older buildings may require upgrades to meet modern appliance loads
• Per-unit water heaters and air conditioners across multiple units simultaneously

Exit Logic

Apato resale depends on:

• A clean, verified rent roll — buyers want documented income, not promises
• Capex timing — a building due for a roof within 2 years prices differently than one freshly renovated
• Buyer financing availability — many lenders cap loan terms for wooden apato at 20–22 years; building age directly affects exit liquidity

NTI Rule: The moment you cannot estimate capex, you should not own the building. If the seller cannot document repair history, that is your answer.

5. Underwriting Detached Homes (Ikkodate)

Detached homes sit between condos and apato in terms of risk profile — you control the entire asset, but structural risk varies widely, and rental demand can be intensely micro-location dependent. A home that rents well in suburban Fukuoka may sit vacant for a year in rural Akita.

Detached-Specific Inputs

• Professional inspection is non-negotiable — crawlspace (床下) and attic (天井裏) checks for moisture, rot, and termite damage are essential for any pre-2000 structure
• Maintenance exposure: roof, exterior walls, gutters, water intrusion pathways
• Insurance and disaster risk — flood zone, landslide zone, and liquefaction risk maps are publicly available and should be reviewed
• Utility constraints: gas type (city gas vs. propane), septic system vs. public sewage, and broadband feasibility
• Landlord-friendly layout: covered parking, storage space, adequate insulation, and sound separation

Vacancy Assumptions

Detached rentals can be stable if:

• The layout genuinely fits family demand — 3LDK or larger with parking is the most lettable configuration
• Location supports daily life: schools within reasonable distance, accessible transport, nearby supermarkets

In rural and semi-rural settings, expect 2–6 months of vacancy between tenants. The tenant pool for detached rentals is narrower than for apartments, and reletting takes longer.

Capex Reserve

Budget moderate-to-high depending on age:

• Roof replacement or major repair: ¥800,000–¥2,500,000 depending on material and size
• Exterior wall repainting: ¥600,000–¥1,500,000
• Plumbing and drainage system upgrades
• Insulation upgrades — older Japanese homes have very poor thermal performance; this affects both tenantability and monthly utility costs
• Termite prevention and treatment (シロアリ対策): required every 5 years in many regions; treatment costs ¥100,000–¥300,000

Exit Logic

Detached homes can be liquid in strong suburban and lifestyle markets — parts of greater Tokyo, Osaka commuter suburbs, and Fukuoka’s expanding residential belt. In rural settings, exit liquidity can be extremely limited, and properties are increasingly common on akiya (空き家) registries for a reason.

NTI Rule: In Japan, “beautiful countryside” is not an exit strategy. Beautiful doesn’t mean liquid.

6. The Stress Test: Run This on Every Deal

A deal that only works under ideal conditions is not a deal — it’s a bet. Run these two scenarios before you commit to any purchase.

Scenario 1: Vacancy Shock

• Condo: Add 1–2 months of vacancy per year beyond your base assumption
• Apato: Vacancy rises by 10–20 percentage points for a 6-month period
• Detached: 3–6 months of vacancy between tenants

Scenario 2: Capex Shock

• Condo: Special assessment levy + full interior refurbishment in the same year
• Apato: Roof replacement + 2 full unit refurbishments occurring simultaneously
• Detached: Roof repair + moisture or termite remediation discovered after purchase

If your cash flow or reserves collapse under either scenario, you are not underwriting — you are hoping. Hope is not a real estate strategy.

7. A Clean Go / No-Go Framework

Condo

• ❌ No-go: Reserve fund is underfunded relative to the repair plan; major structural or façade works are within 3 years
• ✅ Go: Building financials are transparent, reserves are adequate, and management rules align with your rental strategy

Apato

• ❌ No-go: Repair history is undocumented or shows obvious deferred maintenance; building is over 25 years old without verified major renovation work
• ✅ Go: Rent roll is independently verified, capex is buffered, and a reliable management company is already in place

Detached Home

• ❌ No-go: Professional inspection reveals structural moisture, active termite damage, or foundation issues without a clear, costed remediation path
• ✅ Go: Structure is clean, rental demand profile is durable, and the layout genuinely matches the local renter demographic

Final Thoughts

Japan rewards disciplined buyers. The market has low volatility, strong legal protections for property ownership, and a culture of building maintenance that — when documented — makes due diligence reliable. But the rewards go to operators who model deals honestly, not to speculators who project best-case occupancy onto a snapshot rent roll.

A reusable underwriting model is how you buy with discipline — especially from overseas.

If you want help applying this framework to a specific deal or asset type, reach out to the Nippon Tradings team. We work with foreign investors at every stage of the acquisition process in Japan.