Yoshinogawa Valley Mmegharị Ụlọ Isi Ọrụ by Wataru Sato

Yoshinogawa Valley Mmegharị Ụlọ Isi Ọrụ by Wataru Sato is a highly esteemed winner of the very prestigious 2026 Ihe Nrite A' Design Award nke Bronz in Nhazi Ụlọ Owu, Ụlọ na Ihe Owuwu Competition Category.

BronzỤlọ Owu· 2026

Yoshinogawa Valley Mmegharị Ụlọ Isi Ọrụ

by Wataru Sato

Client: KITAOKA Group

Ihe Nrite A' Design Award nke Bronz Winner in Ụlọ Owu Category

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The Design

About Yoshinogawa Valley Mmegharị Ụlọ Isi Ọrụ

Ọrụ a bụ mmegharị nke ụlọ ọrụ e wuru arụ nke gbara afọ 40 na-akwaghị akwatu ya. E tinyere oghere kwụ ọtọ dị mita 50 n'etiti ihe owuwu dị adị, nke kwekọrọ n'okporo ụzọ ọwụwa anyanwụ na ọdịda anyanwụ nke Osimiri Yoshino, na-ahazigharị ụlọ ahụ ka ọ bụrụ nku abụọ dị n'ebe ugwu na ndịda. Akpọrọ ya Ndagwurugwu Osimiri Yoshino, ọrụ oghere a bụ ọkpụkpụ azụ nke ihe owuwu ahụ. Windo elu ụlọ chere ihu n'ebe ugwu na-enye ìhè ehihie kwụsiri ike, ebe ikuku na-agagharị n'onwe ya na-esite n'ọdịiche dị n'ịdị elu na nrụgide. Site n'ịhazigharị ụlọ ahụ, ọrụ a na-ezere ikewa ụkpụrụ ndị ọ na-akwado.

The Recognition

About the Ihe Nrite A' Design Award nke Bronz

Yoshinogawa Valley Mmegharị Ụlọ Isi Ọrụ meriri A' Design Award nke Bronz, nnabata dị oke ugwu e nyere design ndị pụtara ìhè nke a ma ama maka nzụlite ihe, ọgụgụ isi na nghọta. Ndị meriri na Bronz bụ ihe e mere nke ndị nwere nka nke ukwuu ma dị mma n'imepụta nke na-egosi ahụmahụ buru ibu, echiche na ọgụgụ isi nke ndị designer ha. A na-atụ anya na Yoshinogawa Valley Mmegharị Ụlọ Isi Ọrụ ga-abụ ihe a na-asọpụrụ nke ukwuu, a na-eto na a hụrụ n'anya, nke dị oke ọrụ ma dị ọhụrụ. Design a meriri A' Design Award nke Bronz na-agụnye ụzọ kacha mma n'ime nka, sayensị, design na teknụzụ, ma dị mma nke ukwuu maka nlebara anya ya n'obere ihe. Yoshinogawa Valley Mmegharị Ụlọ Isi Ọrụ na-emezu mkpa nke ọma, na-emetụ ọchịchọ aka, na-adọrọ mmetụta obi ma na-adọta ọchịchọ ịmara.

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.