Country Japan

---
name: country-japan
description: >
  Japan architectural code and regulatory reference. Covers the Building Standards Act
  (Kenchiku Kijun Ho, 1950, fundamentally revised 1998 toward performance-based regulation
  and 2007 strengthening post-Aneha incident), Building Standards Law Enforcement Order
  (Kenchiku Kijun Ho Shiko Rei) and MLIT Notifications (Kokuji); the parallel Fire Service
  Act and Fire Service Law Enforcement Order administered by Fire Department (Shobosho);
  Energy Conservation Act 1979 superseded by Act on the Improvement of Energy Consumption
  Performance of Buildings (Kenchikubutsu Sho-Energy Ho) 2015 + amendment 2022; Heart Building
  Law 2006 (Barrier-Free Law) and JIS S 0026 accessibility standards; City Planning Act with
  12 use districts and ratio-based regulation (Yoseki-ritsu volumetric, Kenpei-ritsu coverage,
  daylighting + setback ratios); the unique two-level seismic design philosophy (Level 1
  475-year + Level 2 2475-year), 1981 New Seismic Standard (Shintaishin), Energy Absorption
  Member design + base isolation + damper systems; AIJ Recommendations for Loads on Buildings
  2015; CASBEE (Comprehensive Assessment System for Built Environment Efficiency); BCJ
  (Building Center of Japan) structural performance evaluation; Architect Law and Class 1/2/
  Mokuzo (timber) architect designations; Land + Building Lease Act; and the prefecture +
  Designated City (Seirei Shitei Toshi) + Core City (Chukaku Shi) administrative tiers.
---

# Country: Japan

Architectural code and regulatory reference for projects in Japan (all 47 prefectures + Tokyo Metropolis). Activate this skill on any Japanese city/prefecture reference, JPY currency, mention of "Kenchiku Kijun Ho"/"BSL"/"Sho-Energy Ho"/"CASBEE"/"AIJ"/"BCJ"/"Shintaishin", or Japanese architectural terminology (yoseki-ritsu, kenpei-ritsu, kakunin-shinsei, kanseikensa, joryoku-do, koshou-tatemono, mokuzo).

---

## 1. Regulatory Hierarchy

Japan operates as **Archetype D (Centralised National + Strong-Form Clauses)**. Building regulation is national, administered through prefectures + designated cities under Building Standards Act delegated authority. Some matters are devolved to designated cities.

### 1.1 Authority Stack

```
LEVEL 1 -- NATIONAL
  Ministry of Land, Infrastructure, Transport and Tourism (MLIT, Kokudo Kotsu Sho)
    Housing Bureau (Jutaku Kyoku) -- residential policy
    City Bureau (Toshi Kyoku) -- urban planning
    Land and Real Estate Industry Bureau
    + issues MLIT Notifications (Kokuji) -- detailed technical requirements
  Ministry of Internal Affairs and Communications (Somu Sho) -- Fire Service Agency
  Ministry of Health, Labour and Welfare (Kosei Rodo Sho) -- hospital regulations
  Ministry of Economy, Trade and Industry (METI, Keizai Sangyo Sho) -- energy + product safety
  Ministry of the Environment (Kankyo Sho) -- environmental
  Ministry of Education (MEXT) -- school facilities
  National Police Agency -- some safety regulations

LEVEL 2 -- PREFECTURE (todofuken) + DESIGNATED CITIES
  47 prefectures + 20 Designated Cities (Seirei Shitei Toshi) -- e.g.,
    Tokyo (special category as Metropolis), Osaka, Yokohama, Nagoya, Sapporo, Kobe,
    Kyoto, Fukuoka, Hiroshima, Sendai, Kawasaki, Saitama, Chiba, Niigata, Hamamatsu,
    Sakai, Shizuoka, Okayama, Sagamihara, Kumamoto
  Tokutei Gyousei Cho (Designated Administrative Officer) -- typically prefectural or
    designated-city housing department; oversees Kakunin-shinsei (building confirmation)
  Building Examiners (Kenchiku Shujikan) -- public officials
  Designated Confirmation Inspection Agencies (Shitei Kakunin Kensa Kikan) -- private
    since 1998 reform; competitive choice

LEVEL 3 -- MUNICIPALITY (shi-cho-son)
  Smaller cities, towns, villages -- if not Designated City, defer to prefecture for building
    confirmation but handle planning under City Planning Act
  Local Fire Departments (Shobosho)

LEVEL 4 -- PROJECT
  Kakunin-shinsei (Building Confirmation Application) submitted by Class 1 Architect or
    qualified delegate
  Structural calculations checked: (a) self-check up to threshold (BCJ-evaluated etc.),
    (b) Performance Evaluation by accredited body (BCJ, Japan Engineering Standards
    Foundation, etc.) for taller/special buildings
  Periodic inspection during construction (Kanseikensa)
  Article 7 Inspection (kansei kensa) -- final inspection before occupancy
```

### 1.2 Building Standards Act Structure

The **Building Standards Act 1950** (BSA) was fundamentally reformed in 1998 (introducing performance-based regulation) and amended again in 2007 (post-Aneha falsified structural calculations scandal, which strengthened independent structural review).

Structure:
- **BSA itself (Kenchiku Kijun Ho)** -- legislative framework
- **BSL Enforcement Order (Kenchiku Kijun Ho Shiko Rei)** -- Cabinet Order with detailed implementing regulations
- **BSL Enforcement Regulations (Kenchiku Kijun Ho Shiko Kisoku)** -- Ministerial Order on procedure
- **MLIT Notifications (Kokuji)** -- detailed technical specifications (hundreds)
- **JIS Standards (Japanese Industrial Standards)** -- material + product specifications

### 1.3 Tokyo Special Status

Tokyo Metropolitan Government (Tokyo-to) has 23 special wards (Tokubetsu-ku) functioning as municipalities + the multi-city Tama region. Building confirmation in Tokyo's 23 wards is generally handled by the Tokyo Metropolitan Government Bureau of Urban Development + ward offices for smaller works. Tokyo has its own **Tokyo Metropolitan Ordinance on Building Standards** -- supplements BSA.

---

## 2. Building Standards Act Core Requirements

### 2.1 Building Classification (Yoto Bunkenchiku)

BSA classifies buildings by **use** + **structure** + **scale**:

| Use Category | Description |
|---|---|
| Tokushu Kenchikubutsu | Special Buildings -- assembly, hospital, school, hotel, etc.; many require BCJ structural eval, additional fire requirements |
| Ippan Kenchikubutsu | General Buildings -- offices, factories |

Special structures (high-rise, large span, special concrete) require BCJ structural performance evaluation per BSA Article 20 + sub-clauses.

### 2.2 Yoseki-ritsu + Kenpei-ritsu (Volume Ratio + Coverage)

The two principal Japanese density controls:
- **Yoseki-ritsu (容積率, FAR)** -- total above-grade GFA / lot area; values 50-1300% by use district
- **Kenpei-ritsu (建蔽率, BCR/Building Coverage Ratio)** -- footprint / lot area; values 30-80% by use district

### 2.3 Use Districts (City Planning Act -- 13 categories)

| Use District | Yoseki-ritsu Range | Kenpei-ritsu Range | Use |
|---|---|---|---|
| First Class Low-rise Residential (Daiichi-shu Tei-so Jukyo) | 50-200% | 30-60% | Houses ≤10/12 m height |
| Second Class Low-rise Residential | 50-200% | 30-60% | Similar +small shop |
| First Class Mid/High-rise Residential | 100-500% | 30-60% | Apartments + small commerce |
| Second Class Mid/High-rise Residential | 100-500% | 30-60% | + medium retail |
| First Class Residential | 100-500% | 50-80% | Residential + offices/retail moderate |
| Second Class Residential | 100-500% | 50-80% | + entertainment limited |
| Quasi-Residential | 100-500% | 50-80% | Roads + residential mix |
| Neighbourhood Commercial | 200-500% | 60-80% | Shops + service |
| Commercial | 200-1300% | 80% | Full commerce + tall buildings |
| Quasi-Industrial | 100-500% | 50-80% | Light industrial |
| Industrial | 100-400% | 50-60% | Factory mix |
| Exclusively Industrial | 100-400% | 30-60% | Heavy industry only |
| Field of Tanada | (rural special) | -- | Agricultural |

### 2.4 Sun-Right + Sky-Right + Daylighting (Hisho-mado Jisshin)

A particularly Japanese set of regulations:

- **Daylighting setback (Nichi-sho ki-zen)** -- buildings must allow specified hours of sun (3-5 hours mid-winter) to reach adjacent properties; codified per area; varies by use district
- **Sky exposure plane / road-set-back-ratio plane (Doro Shasen Seigen)** -- imaginary inclined plane from far edge of road; building cannot project beyond
- **Adjacent-property setback plane (Rinchi Shasen Seigen)** -- imaginary plane from neighbor's lot line
- **Northern exposure setback (Hokugawa Shasen)** -- protects northern neighbours from overshadowing
- **Absolute height limit** in low-rise residential -- 10 m or 12 m

These controls collectively shape Japanese urban form -- often producing characteristic "stepped" or "wedding cake" massing.

### 2.5 Structural Articles 20 + Bekkihyo (Annexes)

**BSA Article 20** sets four tiers of structural review:
- **Tier 4 (lightest)** -- low buildings; sample-rule check
- **Tier 3** -- moderate; specific structural calculation
- **Tier 2** -- high-rise or special; advanced calc + BCJ-evaluated
- **Tier 1 (heaviest)** -- super-high-rise or special structural performance; BCJ Performance Evaluation + MLIT Minister Approval required

Tier 1 cases: building > 60 m, or special types (seismic isolation building, special structural performance like FRPs, ultra-light long-span etc.)

### 2.6 Travel Distance + Egress (BSA + Enforcement Order Article 120-122)

| Parameter | Sprinklered | Unsprinklered |
|---|---|---|
| Max travel distance (general) | 50 m | 30 m |
| Max travel distance (assembly, dormitory) | 40 m | 30 m |
| Max travel distance (hospital, ROS-protected) | 50 m | 30 m |
| Min corridor width (Special Buildings >= 200 m2/floor) | 1.6 m double-loaded; 1.2 m single | -- |
| Min corridor width (residential each floor) | 1.2 m double-loaded; 0.9 m single | -- |
| Min stair width (Special Buildings >= 200 m2/floor) | 1.4 m | 1.4 m |
| Min stair width (residential >= 600 m2 total) | 1.2 m | 1.2 m |
| Min door clear width | 800 mm (Special Buildings); 750 mm (general) | -- |

### 2.7 Two Means of Escape

Two means of escape required when:
- Special Buildings any storey > 100 m2
- Mid-rise Residential > 5 storeys (or > 500 m2 floor)
- High-rise > certain thresholds

---

## 3. Seismic Design

### 3.1 Two-Level Seismic Design

The defining feature of Japanese structural design. Building must be safe under:
- **Level 1 (Damage Limit)** -- frequent earthquakes (~50-year return) -- building remains undamaged, structurally elastic. Design seismic shear coefficient C0 = 0.2 (multiplier on weight).
- **Level 2 (Life Safety / Ultimate)** -- rare earthquakes (~475-year return, possibly 2475-year for important structures) -- building may sustain damage but no collapse. Design shear coefficient C0 = 1.0.

The 1981 revision (Shintaishin -- "New Earthquake-Resistance Standard") introduced this two-level approach. Buildings built before 1981 are designated "Kyu-taishin" and many have been retrofitted.

### 3.2 Building Classifications

- **General buildings**: design per Level 1 + Level 2 capacity
- **Important buildings** (hospitals, communications, government, large assembly): design factor higher (~1.5×)
- **Hi-rise buildings** (> 60 m): site-specific seismic motion + dynamic analysis + BCJ performance evaluation
- **Base-isolated (Menshin) buildings**: separate design route + BCJ evaluation
- **Damper (Seishin) buildings**: separate design route

### 3.3 Site Classification + Seismic Coefficients

Japan ground classes (BSA Enforcement Order Article 88):
- **Class 1** (Type 1 ground -- rocky, strong) -- C0 multiplier baseline
- **Class 2** -- alluvial, moderate
- **Class 3** -- soft (e.g., Tokyo Bay landfill) -- highest C0 multiplier

### 3.4 Standards + References

- **Building Standards Act + Enforcement Order Articles 81-87 + 88**
- **AIJ Recommendations for Loads on Buildings 2015** -- Architectural Institute of Japan
- **AIJ Design Standards for Reinforced Concrete Structures (RC), Steel Structures (S), Composite (SRC)**
- **JSCE standards** -- mainly bridges/civil
- **BCJ Performance Evaluation** -- for taller buildings

---

## 4. Fire Safety (Fire Service Act + BSA)

### 4.1 Two Statute System

Japan uniquely operates fire safety under **two statutes**:
- **Building Standards Act** -- "preventive fire-resistance" (Yobo Bosai) -- structural compartmentation, fire-resistance, smoke control DESIGN
- **Fire Service Act (Shobo Ho)** -- "active fire fighting" (Soshou Bosai) -- sprinkler, detection, hose reel, evacuation equipment, fire-fighting

Plans must be approved by **both** Designated Administrative Officer (BSA) **and** Fire Department (FSA).

### 4.2 BSA Fire Provisions

- **Fire-resistant building (Taika Kenchikubutsu)** -- non-combustible structure, fire-resistance rating per height + use
- **Semi-fire-resistant (Junitaika)** -- intermediate
- **Combustible (Mokuzo + similar)** -- limited heights + areas, primarily low-rise residential

Fire-resistance hours:
- Major structural members up to 4 storeys: 1 hour
- 5-14 storeys: 2 hours
- 15+ storeys: 3 hours

### 4.3 Fire Service Act Provisions

- **Sprinklers** required: high-rise above 11 storeys, large floors (>700 m2 special), large theatre, hospital >5 storey etc.
- **Automatic fire alarms** -- per occupancy type + size
- **Indoor fire hose** + **Hose reel** -- per area
- **Smoke-removal equipment** -- per Article 126 BSA Enforcement Order
- **Emergency power** -- 30 minutes minimum, sometimes 60

### 4.4 Stair Smoke Protection

Japan emphasizes **outside-air stair (To-no-zen Kaidan)** -- stairs vented to outside, often via open balcony. Provides smoke-free escape route without requiring positive pressurization.

For tower buildings without external stair access, **smoke-resistance compartments (To-no-zen Shitsu)** are provided -- lobby + stair both pressurized or vented.

### 4.5 Post-Disaster Function -- Important Buildings

Hospitals, fire stations, government emergency operations centres, designated evacuation centres designed for **post-event functionality** -- structural drift limits tighter, redundancies for utilities, separate emergency power.

---

## 5. Energy Code (Sho-Energy Ho)

### 5.1 Act on the Improvement of Energy Consumption Performance of Buildings (Kenchikubutsu Sho-Energy Ho) 2015

Replaced the older Energy Conservation Act 1979 for buildings. Mandatory compliance for:
- **2017**: large non-residential >= 2000 m2
- **2021**: medium non-residential 300-2000 m2
- **2025** (amendment 2022 effective): ALL new buildings including small residential

Compliance demonstrated via:
- **Standard route (BEI -- Building Energy Index)** -- design primary energy / standard primary energy ≤ 1.0
- **Simplified route** for small buildings (≤300 m2) by Web Pro tool
- **Performance route** -- prescriptive UA + ηA values for envelope, similar to U-value + SHGC compliance

### 5.2 Climate Zones (Notification No. 265 of 2015 + revisions)

Japan defines **8 climate zones (Region 1 through Region 8)** based primarily on HDD (heating degree days):

| Zone | Approximate Region | Typical Cities |
|---|---|---|
| Region 1 | Sub-arctic | Hokkaido east + interior (Asahikawa, Kushiro) |
| Region 2 | Cold | Hokkaido west + Tohoku interior (Sapporo, Aomori interior) |
| Region 3 | Cool-cold | Tohoku coast + Hokuriku (Sendai, Akita, Niigata) |
| Region 4 | Cool | Inland Honshu (Nagano interior, Saitama interior) |
| Region 5 | Temperate | Tokyo, Yokohama, Osaka -- main urban regions |
| Region 6 | Mild | Western Honshu, Shikoku (Hiroshima, Takamatsu, Fukuoka) |
| Region 7 | Warm | Southern Kyushu (Kagoshima) |
| Region 8 | Subtropical | Okinawa |

### 5.3 Envelope Targets (Sho-Energy Ho Performance Route)

| Zone | UA (W/m2K) max | ηA (avg solar) max |
|---|---|---|
| 1 | 0.40 | -- |
| 2 | 0.40 | -- |
| 3 | 0.50 | -- |
| 4 | 0.60 | -- |
| 5 | 0.87 | 3.0 |
| 6 | 0.87 | 2.8 |
| 7 | 0.87 | 2.7 |
| 8 | -- | 6.7 (cooling-dominated) |

(UA = average U-value over external envelope; ηA = average solar acquisition factor)

### 5.4 ZEH and ZEB Programs

- **ZEH (Net Zero Energy House)** -- residential; tiered ZEH, ZEH Plus, ZEH+R (resilience-enhanced)
- **ZEB (Net Zero Energy Building)** -- non-residential; tiered ZEB, Nearly ZEB, ZEB Ready, ZEB Oriented

METI subsidies tied to these tiers.

### 5.5 CASBEE -- Comprehensive Assessment System for Built Environment Efficiency

Japan's own green building assessment system, comparable to LEED + DGNB. Rates by:
- **BEE (Built Environment Efficiency)** = Q (Quality) / L (Load) ratio
- Categories: S, A, B+, B-, C
- Multiple sub-tools: CASBEE for Buildings (New, Existing, Renovation), Urban Development, Cities

Many municipalities require CASBEE B+ or A as minimum for medium-large buildings.

---

## 6. Accessibility (Heart Building Law 2006)

### 6.1 Heart Building Law (Hito ni Yasashii Machizukuri / Barrier-Free Law)

**Act on Promotion of Smooth Transportation of Elderly, Disabled Persons (2006)** -- consolidated previous Heart Building Law + Traffic Barrier-Free Law.

Mandatory provisions for:
- **Designated Buildings**: shops > 2000 m2, hospitals, hotels (> 50 rooms), restaurants > 200 m2, theatres + schools above certain size, public buildings
- **Specific Designated Buildings**: subset with stricter standards

### 6.2 Key Dimensions (Heart Building Law + JIS S 0026)

| Element | Dimension |
|---|---|
| Accessible route | 1.2 m (1.5 m preferred); passing space 1.4 x 1.4 m every 50 m |
| Door clear width | 800 mm |
| Ramp gradient | 1:12 max; landings every 6 m run + at top/bottom |
| Lift cabin | 1100 x 1350 mm (Type 1); 1400 x 1600 mm (Type 2 hospital) |
| Accessible WC | 2.0 x 2.0 m; with multi-function: 2.2 x 2.2 m |
| Accessible parking | 3.5 m + access; covered preferred |
| Tactile flooring | Per JIS T 9251; at platform edges, ramps, stair tops, level changes |

### 6.3 Provision Counts

- **Accessible parking**: 1 per 50 stalls (designated buildings)
- **Multi-Function Toilet** (Tashinooyo Toiret): at least 1 per floor in designated buildings -- combines accessible WC + diaper change + ostomy + emergency call
- **Hotel accessible rooms**: 1 per 50 rooms (designated)
- **Tactile guidance**: comprehensive in transit + public buildings

### 6.4 Universal Design Beyond Compliance

Japan's robust UD culture extends beyond legal minimum:
- Many municipalities have Universal Design Mark / Tsugou (Convenience) certifications
- "ChojuJuutaku" (Long-Life Quality Housing) certification for housing
- "Tokutei Hyouka" Designated Evaluation for housing accessibility

---

## 7. Structural Materials and Standards

### 7.1 Material Codes

| Material | Reference |
|---|---|
| Reinforced Concrete | AIJ-RC / JASS 5 |
| Steel Structures | AIJ-S / JASS 6 |
| Composite (Steel-Reinforced Concrete -- SRC) | AIJ-SRC |
| Wood / Timber | AIJ-W / JASS 11 / JAS lumber + glulam standards |
| Masonry | AIJ-M / JIS A 5406 (block) |
| Foundations | AIJ-F / BSA Articles + JIS A 5525 (piles) |

### 7.2 JIS Standards

The Japanese Industrial Standards (JIS) provide product-level specifications:
- JIS A series -- civil + building
- JIS B -- machinery
- JIS C -- electrical
- JIS G -- iron + steel

### 7.3 Wind (AIJ Recommendations 2015)

Japan uses **basic wind velocity (Vref)** at 30 m height -- varies city by city per AIJ map. Tokyo Vref = 34 m/s. Okinawa coastal (typhoon-prone) Vref up to 46 m/s.

Wind-resistant design also separate consideration:
- **Wind-cycle fatigue** for tall buildings
- **Aerodynamic shape coefficients** per wind tunnel testing for >60 m
- **Cyclonic/typhoon design** distinct from synoptic wind, especially in Okinawa + Kyushu

---

## 8. Permit Workflow

### 8.1 Standard Workflow (Kakunin-shinsei)

1. **Pre-application consultation** (Jizen Sodan) with prefecture/Designated City Building Department
2. **Preliminary calculations** by Class 1 Architect (Ichi-kyu Kenchikushi)
3. **Submit Building Confirmation Application (Kakunin-shinsei)** to designated administrative officer OR private confirmation inspection agency
4. **Confirmation Certificate issued (Kakunin Tsuuchi-sho)** within statutory period (varies; 7-35 days)
5. **Structural Calculation Conformance Judgment (Kouzou Keisan Tekigosei Hantei)** -- if Tier 2/3 structural -- by accredited body
6. **Performance Evaluation** by BCJ (or other accredited) -- if Tier 1 structural
7. **MLIT Minister Approval** -- if super-high-rise OR special structure
8. **Periodic Inspections during construction** (Chuukan Kensa)
9. **Article 7 Inspection** (Kanseikensa) -- final
10. **Inspection Certificate (Kanseikensa-Shomeisho)** -- equivalent to certificate of occupancy

### 8.2 Architect Licensing

- **Class 1 Architect (Ichi-kyu Kenchikushi)** -- can design any building scale
- **Class 2 Architect (Ni-kyu Kenchikushi)** -- limited to certain scales/structures
- **Mokuzo Kenchikushi (Wood-Structure Architect)** -- limited to wooden buildings
- Examinations administered by MLIT-designated body; renewed periodically with CPD

### 8.3 Special Buildings -- Building Center of Japan (BCJ) Role

BCJ evaluates buildings beyond standard limits:
- **Super-high-rise** (>60 m) -- structural performance evaluation
- **Base-isolated** (Menshin)
- **Special structural systems** (cable-stayed, tensile, etc.)
- **Long-span** structures
- **Special materials** (CLT large-scale, etc.)

BCJ issues evaluation certificate which the Confirmation Inspection Agency relies on.

---

## 9. Climate Design Parameters

### 9.1 Tokyo (Region 5)

| Parameter | Value |
|---|---|
| Cooling design DB (0.4%) | 32-34 deg C |
| Cooling design WB | 26-27 deg C |
| Heating design DB (99.6%) | 0 to -2 deg C |
| Annual CDD (base 18C) | 1100-1300 |
| Annual HDD (base 18C) | 2000-2200 |
| Annual GHI | 1400 kWh/m2 |
| Wind 3-sec gust (typhoon) | 50-55 m/s 0.4% probability |
| Snowfall | < 100 mm typical / yr |

### 9.2 Sapporo (Region 2)

| Parameter | Value |
|---|---|
| Heating design DB | -8 to -10 deg C |
| Annual HDD | 3500+ |
| Snow ground load | 1.5-3.5 kN/m2 (depends on neighbourhood) |

### 9.3 Okinawa (Region 8)

| Parameter | Value |
|---|---|
| Cooling design DB | 32-33 deg C |
| Cooling design WB | 28 deg C |
| Annual CDD | 5000+ |
| Annual HDD | ~50 |
| Typhoon wind | extreme; design 60+ m/s 3-sec gust |
| Salt-laden corrosion | severe |

---

## 10. Quick Numeric Reference

| Parameter | Value | Source |
|---|---|---|
| Floor-to-floor residential | 2.8-3.0 m | BSA + practice |
| Floor-to-floor office | 3.5-4.0 m | Class A spec; 2.5 m min clear |
| Hotel ceiling clear | 2.4 m min | BSA |
| Corridor width residential (multi-storey) | 1.2 m | BSA Enforcement Order 119 |
| Corridor width Special Building | 1.6 m | BSA Enforcement Order 119 |
| Stair width residential | 1.2 m | BSA Enforcement Order 23 |
| Stair max riser | 23 cm (residential); 18 cm (Special) | BSA |
| Stair min going | 15 cm (residential); 24 cm (Special) | BSA |
| Travel distance sprinklered (general) | 50 m | BSA Enforcement Order 120 |
| Seismic C0 (Level 1) | 0.2 | BSA + AIJ-S |
| Seismic C0 (Level 2) | 1.0 (general); 1.5 (important) | BSA + AIJ-S |
| UA Tokyo (Region 5) | 0.87 W/m2K max | Sho-Energy Ho |
| Yoseki-ritsu Commercial | 200-1300% | City Planning Act |
| Kenpei-ritsu Residential | 30-60% | City Planning Act |
| Daylight hours required (Region 5 winter) | 3 hours mid-winter | Local ordinance |

---

## 11. Application Workflow

1. **Identify prefecture / Designated City** (or special wards in Tokyo).
2. **Identify use district + yoseki-ritsu + kenpei-ritsu + height limit + daylighting setbacks**.
3. **Determine if Special Building (Tokushu Kenchikubutsu)**.
4. **Determine structural review tier** (1, 2, 3, 4) per BSA Article 20.
5. **Apply BSA + Enforcement Order + MLIT Notifications** for general design.
6. **Apply Fire Service Act + Local Fire Department** for fire-fighting systems.
7. **Apply Sho-Energy Ho** for energy.
8. **Apply Heart Building Law** if Designated Building scale.
9. **Apply AIJ-RC / AIJ-S / AIJ-W standards** for structural materials.
10. **Engage BCJ or other accredited body** if structural performance evaluation needed.
11. **Cite clauses**: "Building Standards Act Article 20", "BSA Enforcement Order Article 120", "MLIT Notification 1457 of 2000 (Kokuji)", "AIJ Recommendations for Loads on Buildings 2015", "Sho-Energy Ho 2015 Article 11", "Heart Building Law Implementation Standards Section 13".

---

## 12. Authoritative Sources

- **MLIT (Ministry of Land, Infrastructure, Transport and Tourism)** -- mlit.go.jp
- **Building Center of Japan (BCJ, Nihon Kenchiku Center)** -- bcj.or.jp -- structural evaluation, technical guidelines
- **Japan Architectural Institute (AIJ, Nihon Kenchiku Gakkai)** -- aij.or.jp -- structural recommendations
- **Architectural Institute of Japan -- JASS series** -- Japanese Architectural Standard Specifications
- **JIS via Japan Standards Association (JSA)** -- jsa.or.jp
- **Fire and Disaster Management Agency (FDMA, Shobo Cho)** -- fdma.go.jp
- **Japan Society of Civil Engineers (JSCE)** -- jsce.or.jp
- **Institute for Building Environment + Energy Conservation (IBEC)** -- ibec.or.jp -- CASBEE
- **METI (Ministry of Economy, Trade and Industry)** -- meti.go.jp -- ZEB/ZEH subsidies
- **Japan Sustainable Building Database (CASBEE certified projects)** -- ibec.or.jp/CASBEE
- **Tokyo Metropolitan Government Bureau of Urban Development** -- toshiseibi.metro.tokyo.lg.jp
- **Each prefecture building department** -- prefectural government websites
- **Architect license examination via Japan Architects Association** -- jia.or.jp

---

*Cross-references: load `building-codes` for general code structure (Japan BSA is distinct -- two-statute fire system); `fire-life-safety` for general principles overlaid by BSA fire-resistance + Fire Service Act active provisions; `accessibility-design` for global frameworks then Heart Building Law; `building-sustainability` for CASBEE + LEED + Passivhaus comparison; `structural-systems` for seismic-specific design (Japan two-level + base isolation expertise); `building-envelope` for severe climate (subarctic to subtropical) + typhoon detailing.*