Yamashita Sekkei

What Yamashita Sekkei does

Yamashita Sekkei is a Tokyo-headquartered architectural design firm founded in 1928 (97 years operating as of 2026, approaching its planned centennial in 2028) that provides integrated architectural design combining architectural design (意匠), structural engineering (構造), and building equipment systems (設備) within a unified process. It operates through a Tokyo headquarters, five regional branches (Hokkaido/Sapporo, Tohoku/Sendai, Chubu/Nagoya, Kansai/Osaka, Kyushu/Fukuoka), satellite offices in Yokohama, Fukushima, Kanazawa, and Okinawa, and a Yangon overseas representative office. The firm holds ISO9001 (1998) and ISO14001 (2000) certifications, is registered as a first-class architect office under Tokyo Governor Registration No. 958, and has Eruboshi Level 2 certification for gender equality in the workplace. The documented technical workforce totals 433 engineers at the parent firm including 282 first-class architects, 25 structural first-class architects, 22 equipment-design first-class architects, 61 building equipment engineers, and 13 technical engineers (技術士).

The firm monetizes professional service fees across four service lines: Project Management (事業計画マネジメント), Architectural Design & Urban Design (建築設計・都市デザイン), Construction Supervision (工事監理), and Management & Operations Support (管理・運営支援). Go-to-market is via competitive bidding (プロポーザル), design competitions, and direct commissions, frequently through joint ventures with general contractors and construction firms (Takenaka, Fujita). Customer segments are primarily Japanese public sector (municipal, prefectural, and national government offices, civic facilities), with secondary exposure to healthcare (general hospitals, children's hospitals, medical centers), education (universities, K-12 schools), commercial/corporate real estate, and social infrastructure (sports arenas, cultural halls, welfare facilities). Pricing is project-based with no public disclosure of fee schedules; salaries disclosed for new graduates (¥350,000/month graduate school; ¥330,000/month university) imply standard Japanese professional-services compensation. The firm maintains two wholly-owned subsidiaries — Yamashita PMC (project management consulting, est. 1997) and Yamashita Technos (technical services, est. 1975) — extending the group's service surface.

Proprietary technical capabilities are concentrated in structural and environmental engineering: structural technologies include Green Mass Damper, Skip-Flow Damper, seismic isolation retrofit, membrane structure, prestressed cable beam, hybrid PC, and RC shell; environmental technologies include environmentally-conscious facades, ground-source heat utilization, rooftop/wall greening, natural daylighting, night purge cooling, and natural ventilation systems. The firm offers ZEB (Zero Energy Building) planning as a specialized service, reporting that 2025 design/consulting ZEB share exceeded the 50% internal target, with a 2030 target of 100% ZEB adoption for new building design/consulting services and a 20%+ increase in existing-building ZEB retrofit work. Recent product initiatives include the March 2026 co-development of an interior window-installed perovskite solar cell unit (building-integrated photovoltaics) and the June 2026 completion/opening of THE NEXTT HOTEL. The firm holds extensive industry recognition (multiple BCS Awards, Good Design Awards, public architecture awards, JIA Excellent Architecture selections, lighting awards, and SDG-related recognitions across 2017-2025) and is preparing for its 2028 centennial under the founder's stated philosophy of 'sincerity to clients' (クライアントへの誠実).

Name

Yamashita Sekkei

Legal name

株式会社山下設計

Website

https://yamashitasekkei.co.jp

Company type

Private

Founded year

1928

Operating status

Operating

Headcount range

251–500 employees

Short description

Yamashita Sekkei is a Tokyo-headquartered architectural design firm founded in 1928 providing integrated architectural, structural, and building equipment engineering services to public-sector, healthcare, education, and commercial clients across Japan through its headquarters, five regional branches, and a Yangon overseas office.

Ownership category

akta.pro rank

Product category

Architectural Design Services

NAICS

Architectural Services (54131), Architectural, Engineering, and Related Services (5413), Engineering Services (54133)

SIC

Services-Engineering Services (8711), Services-Engineering, Accounting, Research, Management (8700)

akta.pro primary industry

Architectural Design Services (BPAHAKAA)

akta.pro secondary industries

Building Information Modeling (BIM) & Digital Design Services (BPAHAKAK), Green Building & Energy-Efficient Construction (LEED, Weatherization) (EDAOAAAO)

Keywords

• Architectural design services
• Structural engineering consulting
• Construction supervision services
• ZEB building planning
• Facility lifecycle management

Headquarters

HQ city

Chuo

HQ country

Japan

HQ region

Asia

Offices11 records

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Technology or R&D, Marketing or Sales, Infrastructure

Revenue model

1. Architectural Design Services: Fees for architectural design services covering the full project lifecycle from concept through construction documentation, including architectural, structural, and MEP engineering design.
2. Construction Supervision (工事監理): Fees for construction supervision and management services ensuring buildings are constructed according to design specifications, verified through inspection and quality assurance.
3. Project Management (プロジェクトマネジメント): Fees for project management services including business planning, PM (プロジェクトマネージャー) services, and comprehensive project coordination from planning through completion.
4. Management and Operations Support: Fees for building lifecycle management, facility management, and operational support services including building diagnostics, BCP planning, and sustainability consulting.

Pricing tiers

Go-to-market motion2 records

Distribution channels3 records

Marketing channels5 records

Core offering

Yamashita Sekkei provides integrated architectural design services for buildings and urban environments, combining architectural design, structural engineering, and building equipment engineering within a single project delivery framework. The firm also delivers construction supervision, project and business planning, and lifecycle management and operations support, with deep in-house capabilities in seismic-resistant structural technologies and energy-efficient environmental design including ZEB (Zero Energy Building) planning.

Product overview

Yamashita Sekkei is a comprehensive architectural design firm offering an integrated portfolio of four core services: Project Management, Architectural Design & Urban Design, Construction Supervision, and Management & Operations Support. The firm specializes in specialized areas including ZEB (Zero Energy Building) planning and holds advanced technical expertise in structural engineering (green dampers, seismic isolation, membrane structures) and environmental technologies (geothermal systems, natural ventilation). The company serves diverse sectors including offices, government/administrative, education, cultural facilities, healthcare/welfare, commercial, industrial, and residential buildings, with documented expertise in sustainable architecture and environmental design.

Differentiator

Problem solved

Functional benefit

Quantifiable outcome

• 2030 ZEB Target: 100% ZEB adoption rate for new building design and consulting services; 20%+ increase in existing building ZEB projects
• +1 more outcomes

Named customers12 records

Segments5 records

Ideal customer profiles5 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature4 records

Partnerships

Five partnerships are on record, tiered core and minor.

• 株式会社山下PMC (Yamashita PMC)coreOthersRelated company established in 1997 (株式会社山下ピー・エム・コンサルタンツ, renamed to Yamashita PMC) providing project management and consulting services. Located at Tokyo Nihonbashi. Core group company supporting the Yamashita Sekkei group ecosystem.
• 株式会社山下テクノス (Yamashita Technos)coreOthersRelated company established in 1975 providing technical services within the Yamashita group. Core group company supporting technical delivery alongside Yamashita PMC.
• 竹中工委店 (Takenaka Corporation)minorStrategic or Co-development PartnerConstruction contractor for the Ritsumeikan University Osaka Ibaraki Campus project. Yamashita Sekkei performed basic design, design management oversight, and CM services; Takenaka performed implementation design and construction supervision.
• フジタ (Fujita Corporation)minorStrategic or Co-development PartnerECI (Early Contractor Involvement) partner for Saitama Ishinkai Hospital project. Yamashita Sekkei performed basic design; Fujita participated in implementation design under ECI arrangement.
• 氏デザイン (Ushi Design)minorStrategic or Co-development PartnerSign design specialist for Takasaki Arena project. External contributor collaborating with the Yamashita design team on arena signage design as part of integrated project delivery.

Scale indicators4 records

Recent moves12 records

Expansion highlights5 records

Direct peers

• Mitsubishi Jisho Sekkei: Major Japanese architectural design firm affiliated with the Mitsubishi group. Comparable in scale and integrated design capability, with strong public-sector and corporate client bases across Japan.
• Nikken Sekkei: Largest architectural design firm in Japan with similar integrated architectural, structural, and MEP engineering capabilities. Directly comparable on public-sector bidding, integrated design approach, ZEB specialization, and national branch footprint — they are Yamashita's most direct large-scale competitor.
• Nihon Sekkei: Mid-to-large Japanese architectural design firm with similar nationwide coverage, public-sector focus, and integrated design approach. Competes head-to-head on municipal, education, and healthcare tenders.
• Azusa Sekkei: Japanese architectural design firm with similar public-sector focus and integrated engineering capabilities. Competes on similar municipal and healthcare project categories across Japan.

Regional players

• HDR Inc. Global architecture and engineering firm with healthcare specialization. Comparable on hospital design expertise where Yamashita has built a strong track record (e.g., Aichi Medical University, Fukuoka Children's Hospital), though HDR primarily serves North American clients.

Emerging players

• Arup: Global engineering and design consultancy with a growing Japan presence. Competes on complex structural engineering, seismic isolation, and sustainability-driven design mandates where international credentials matter.
• AECOM: Global design and engineering firm with Japan offices. Targets large-scale infrastructure, transportation, and commercial developments where integrated global design capability is a differentiator versus domestic-only firms.

Broad incumbents

• Takenaka Corporation: One of Japan's largest general contractors with significant in-house architectural design capabilities. While a construction company, Takenaka competes for integrated design-build mandates and is a frequent JV partner with Yamashita.
• Obayashi Corporation: Large Japanese general contractor with in-house design capability. Comparable to Takenaka and Kajima as a design-build competitor on civic, healthcare, and education projects.
• Kajima Corporation: Major Japanese general contractor with a dedicated architectural design division. Competes with Yamashita on large-scale integrated public and commercial projects where design-build delivery is required.

Market position

Strengths4 records

Weaknesses5 records

Competitive moat6 records

Key risks5 records

Key highlights7 records

Customer concentration

• LinkedInlinkedin.com/company/yamashita-sekkei-inc

Compliance3 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles22 records

Subsidiaries2 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Yamashita Sekkei