Kitaoka Group总部办公楼改造项目丨日本丨东京Wataru Architects工作室

A fifty-metre-long skylight cuts through the centre of Kitaoka Group Head Office Building, renovated by Tokyo studio Wataru Architects in Mima City, Japan.

Wataru Architects redesigned the 40-year-old building belonging to construction company Kitaoka Group into an open, light-filled office with a strong connection to the surrounding landscape and local community.

Wataru Architects has renovated Kitaoka Group's headquarters in Japan

"The project aims to redefine the values of working environments in Japan, starting from the local context," Wataru Architects principal Wataru Sato told Dezeen.

"This integration embraces the surrounding natural landscape and fosters communication among employees, their families and the broader community," Sato said.

A five-metre cantilevered canopy extends from the entrance

While the majority of the office's prefabricated steel structure was retained, it was split into two long and narrow halves, nodding to the valley on either side of the nearby Yoshino River.

In the middle, the studio introduced an atrium topped by a continuous skylight that runs along the length of the roof, flooding the interior with daylight.

This atrium connects the ground and first floors, allowing for natural ventilation and improving what the studio described as a previously dark and disconnected layout.

"The existing building has been transformed by a luminous void that draws daylight and a breeze deep into the interior," said Sato. "As the atrium spans the full depth of the building, airflow is evenly dispensed, delivering a gentle breeze to every corner."

A seven-metre-tall tree sits at the heart of the plan

Opting for a pared-back interior scheme, Wataru Architects combined original tiling with plywood panels and neutral finishes, in contrast with red-painted beams and pops of greenery.

This includes a seven-metre-high Benjamin tree at the centre of the plan and a selection of plants that are dotted throughout the interior.

The ground floor is open to family members

"The palette embraces low-contrast tones, blending diverse textures and layered paint hues to create depth," said Sato.

The ground floor is designed as a public space where employees can work while also being open to families and community members.

A 50-metre-long skylight spans the length of the building

Outside, the building's entrance has been updated with a five-metre-long cantilevered canopy, while the facade has been revamped with operable glass sashes to invite airflow.

Around the entrance, the landscape has been turned into a park for the local community, finished with layered vegetation and "an oversized 3D-printed vase".

A central atrium connects the ground and first floor spaces

Limiting the environmental impact of the project was a key aspect of the studio's approach, which involved reusing the existing structure and finishes, as well as harnessing natural light and ventilation.

"The design maximises natural light and ventilation, eliminating the need for daytime lighting and reducing air conditioning depending on the seasons," Sato stated.

The studio opted for a pared-back interior palette

Kitaoka Group office headquarters is shortlisted in the small workplace project category of the Dezeen Awards 2025.

Other projects in the category include an experimental whisky lab by Barthélémy Grino and JSa's self-designed studio in a Mexican factory.

The photography is by Keita Yamamoto.