Yoshinogawa Valley Renovacion del Bastiment del Sèti Social by Wataru Sato

Yoshinogawa Valley Renovacion del Bastiment del Sèti Social by Wataru Sato is a highly esteemed winner of the very prestigious 2026 A' Design Award de Bronze in Arquitectura Competition Category.

BronzeArquitectura· 2026

Yoshinogawa Valley Renovacion del Bastiment del Sèti Social

by Wataru Sato

Client: KITAOKA Group

A' Design Award de Bronze Winner in Arquitectura Category

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Verified Award Winner

Verify Award Status for #175868

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The Design

About Yoshinogawa Valley Renovacion del Bastiment del Sèti Social

Aqueste projècte es una renovacion d'un bastiment de burèus prefabricat de 40 ans sens demolicion. Un vuege linear de 50 mètres es inserit al centre de l'estructura existenta, alinhat amb l'axe èst-oèst de la ribièra Yoshino, reorganizant lo bastiment en doas alas nòrd-sud. Nomenada Val de la Ribièra Yoshino, aquesta operacion espaciala forma l'esquina de l'arquitectura. Una lucana orientada cap al nòrd provesís una lutz natural establa, mentre qu'una ventilacion passiva es generada per de diferéncias de nautor e de pression. En reorganizant lo bastiment, lo projècte evita de devesir las valors que sosten.

The Recognition

About the A' Design Award de Bronze

Yoshinogawa Valley Renovacion del Bastiment del Sèti Social a ganhat la distincion A' Design Award de Bronze, una reconeissença plan prestigiosa acordada a de designs excellents que se destrian per la creativitat, l'engenh e la finessa. Los ganhaires del Bronze son d'artefactes largament abils e sorprenentament creatius que provan la vasta experiéncia, l'imaginacion e l'engenhositat de lors designers. S'espèra que Yoshinogawa Valley Renovacion del Bastiment del Sèti Social siá un objècte fòrça considerat, admirat e estimat, notablament professional e innovant. Aqueste design ganhaire de la distincion A' Design Award de Bronze integra las melhoras practicas de l'art, de la sciéncia, del design e de la tecnologia e es excellent per son atencion al detalh. Yoshinogawa Valley Renovacion del Bastiment del Sèti Social satisfa esplendidament los besonhs, toca los desirs, encanta los sentiments e interèssa la curiositat.

Behind the Design

Press Kit

Credits, team members and technical details provided by the designer.

Unique Properties: Inspired by the Yoshinogawa River, the design translates the structure of a valley into architecture. By dividing the existing building into two volumes and inserting a linear void, a valley-like interior is created.
A 50-meter skylight brings daylight inside, while the void enables ventilation, greenery, and social interaction. This configuration integrates environmental elements into the workplace.
Through renovation, the design reinterprets an existing office and proposes a new spatial model.
Dimensions & Packaging: A valley-like void and continuous skylight are introduced at the center of a 50-meter prefabricated office building. The two-story void brings daylight to the ground floor and enhances natural ventilation.
A 7-meter Benjamin fig tree is placed at the center, visible from both levels. Planting along the void forms a layered green environment connected to the exterior.
Existing structure and finishes are retained, creating a composition where old and new materials coexist.
Tags: Prefabricated office renovation, open lounge, atrium and skylight, regional architecture, nature-inspired workspace, Yoshino River
Production Technology: The project renovates an existing prefabricated office building without demolition.
A central valley-like void integrates daylight, ventilation, and greenery. Continuous skylights provide stable north light, while passive ventilation is driven by height and pressure differences.
Spatial organization is redefined as an environmental system, reducing reliance on mechanical equipment. Existing structure and finishes are retained, forming a layered expression and a sustainable model for reuse.
Design Challenge: The primary challenge was to renew the environmental and social value of a deteriorated prefabricated office without demolition or new construction.
Introducing a skylight and central void into an enclosed structure required coordination of structural, safety, and cost constraints.
Rather than relying on equipment, the design redefines spatial organization as an environmental system.
The project shows that architectural operations can generate new value within existing buildings.
Research: This research examines how renovation can achieve environmental performance comparable to new construction.
A skylight and central void introduce daylight and passive ventilation, reducing reliance on mechanical systems.
Monitoring shows that artificial lighting is unnecessary during daytime and HVAC demand is reduced. Annual energy decreased by about 73,000 kWh, with savings of 65% in lighting and 30% in air conditioning.
The project presents a replicable model for sustainable renovation.
Inspiration: The project draws inspiration from the Yoshinogawa River, known as the Mother River of Tokushima.
Rather than referencing its form directly, the design interprets the river as a spatial structure.
By inserting a linear void through the existing building, the architecture transforms the logic of a valley into an interior condition, bringing light, wind, and greenery deep into the space, while also inviting relationships among people, families, and the local community.
Project Duration: The project started in January 2023 in Miyoshi Town, Tokushima Prefecture, Japan, and was completed in August 2024.
Operation Flow: The building transforms a closed office into an open environment accessible to families and the local community.
The central valley acts as a social axis supporting movement, staying, and interaction. The ground floor serves as a shared space, while the upper floor provides flexible work areas.
Users are not assigned fixed workplaces but choose spaces as needed. Through everyday use, the project encourages informal encounters and redefines how work and social life coexist.
Image Credits: Image #1: Photographer Keita Yamamoto (Architectural Photography), Kitaoka Group Headquarters Renovation, 2024.
Image #2: Photographer Keita Yamamoto (Architectural Photography), Kitaoka Group Headquarters Renovation, 2024.
Image #3: Photographer Keita Yamamoto (Architectural Photography), Kitaoka Group Headquarters Renovation, 2024.
Image #4: Photographer Keita Yamamoto (Architectural Photography), Kitaoka Group Headquarters Renovation, 2024.
Image #5: Photographer Keita Yamamoto (Architectural Photography), Kitaoka Group Headquarters Renovation, 2024.