Yoshinogawa Valley Headquarters Building Renovation

When I first visited the building, what impressed me most was not the building itself, but the landscape of the Yoshino River stretching beyond it. In particular, I noticed that the river and the building were aligned along almost the same axis, and this observation became the starting point of the project.The Yoshino River and the surrounding valley are often referred to as the “mother river” of Tokushima Prefecture, having historically nurtured the region’s culture and industry. I wondered whether bringing the river’s axis of flow into the building as a linear void could generate new flows of people, culture, and activity within Kitaoka-group headquarters. To achieve this, we divided the building into two wings centered around the entrance and inserted a 50-meter-long linear void between them.We call this space the “Valley of Light.” By allowing light, wind, views, and human activity to pass through the building, we sought to bring the presence of the Yoshino River into the interior and transform it into a new organizing principle for the entire architecture.

In Japan, many anonymous existing buildings are replaced through a cycle of demolition and reconstruction. However, although this building was over forty years old, it had been built under post-1981 seismic regulations and its structural frame remained in excellent condition. We began the design process by asking a simple question: “Does it really need to be demolished?”Existing buildings accumulate layers of time, memory, and relationships with their communities—qualities that never appear on drawings. Rather than tearing the building down and starting over, we believed it was possible to create new value while preserving and activating those accumulated qualities.There are countless buildings of the same generation throughout Japan. Through this project, we wanted to propose the idea that such buildings are not only reusable, but can also be transformed into architecture with a level of originality that sometimes exceeds that of new construction.

Before improving mechanical systems, we first considered space itself as an environmental device.The central void and skylights bring natural daylight deep into the building, significantly reducing the need for artificial lighting during the day. At the same time, the vertical movement of air created by the void promotes natural ventilation and helps reduce cooling and heating loads.As a result, primary energy consumption was reduced by approximately 30 percent compared to the building before renovation. We believe environmental performance should not be something added afterward through equipment alone; it should emerge from the spatial composition itself. The form of architecture should generate environmental performance, and energy reduction should be a consequence of that design logic. This was the architectural approach we sought to realize.