Yoshinogawa Valley Rénovasi Wangunan Kantor Pusat by Wataru Sato

Yoshinogawa Valley Rénovasi Wangunan Kantor Pusat by Wataru Sato is a highly esteemed winner of the very prestigious 2026 A' Design Award Perunggu in Arsitéktur Competition Category.

PerungguArsitéktur· 2026

Yoshinogawa Valley Rénovasi Wangunan Kantor Pusat

by Wataru Sato

Client: KITAOKA Group

A' Design Award Perunggu Winner in Arsitéktur Category

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The Design

About Yoshinogawa Valley Rénovasi Wangunan Kantor Pusat

Proyék ieu mangrupa rénovasi wangunan kantor prefabrikasi anu umurna 40 taun tanpa ngabongkar. Rohangan kosong (void) linier 50 méter diselapkeun di tengah struktur anu geus aya, sajajar jeung sumbu wétan-kulon Walungan Yoshino, sarta ngatur ulang wangunan jadi dua jangjang kalér-kidul. Dingaranan Lebak Walungan Yoshino, operasi spasial ieu jadi tulang tonggong arsitékturna. Skylight anu nyanghareup ka kalér nyadiakeun cahya panonpoé anu stabil, sedengkeun véntilasi pasif dihasilkeun tina bédana jangkungna jeung tekanan. Ku ngatur ulang wangunan, proyék ieu nyingkahan misahkeun ajén-inajén anu dirojongna.

The Recognition

About the A' Design Award Perunggu

Yoshinogawa Valley Rénovasi Wangunan Kantor Pusat mangrupa juara A' Design Award Perunggu, pangakuan anu pohara bergengsi anu dipasihkeun ka desain unggul anu dicirikeun ku kréativitas, kacerdikan jeung kawaspadaan. Para juara Perunggu téh artéfak anu lobaan kaahlian jeung kréatif pisan anu ngabuktikeun pangalaman anu lega, imajinasi jeung kacerdasan para désainerna. Yoshinogawa Valley Rénovasi Wangunan Kantor Pusat diharepkeun jadi objék anu dihargaan, dikagumi jeung dipikanyaah anu profésional jeung inovatif. Desain juara A' Design Award Perunggu ieu ngalebetkeun prakték pangalusna dina seni, élmu, desain jeung téknologi, sarta unggul dina perhatian kana détail. Yoshinogawa Valley Rénovasi Wangunan Kantor Pusat minuhan kabutuhan kalayan éndah, nyentuh kahayang, nyenangkeun rasa, jeung narik rasa panasaran.

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.