How a 50-Meter Skylight Transformed This Japanese Office Into a Light-Filled Community Hub

A Luminous Transformation in Mima City

A fifty-metre-long skylight dramatically cuts through the center of the Kitaoka Group Head Office Building, completely revitalizing this 40-year-old structure through a thoughtful renovation by Tokyo-based Wataru Architects. Located in Mima City, Japan, this project redefines what a modern workplace can be.

Redefining Japanese Work Environments

Wataru Architects principal Wataru Sato explained the project's ambitious vision: "The project aims to redefine the values of working environments in Japan, starting from the local context. This integration embraces the surrounding natural landscape and fosters communication among employees, their families and the broader community."

Architectural Innovation Through Light and Space

The architects retained most of the building's prefabricated steel structure but made a bold move by splitting it into two long, narrow halves - a design choice that nods to the valley on either side of the nearby Yoshino River.

At the heart of the transformation lies the central atrium topped by that continuous skylight, which floods the interior with natural daylight. This luminous void connects the ground and first floors, allowing for natural ventilation and completely transforming what was previously a dark, disconnected layout.

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

Thoughtful Material Palette and Greenery

The interior scheme embraces a pared-back aesthetic that combines original tiling with plywood panels and neutral finishes. Strategic pops of color come from red-painted beams and abundant greenery, including a stunning seven-metre-high Benjamin tree at the center of the plan.

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

Community-Focused Design Approach

Perhaps most innovative is how the ground floor functions as a public space where employees can work while remaining open to families and community members. This blurring of boundaries between work and community life represents a significant shift in Japanese office culture.

Sustainable Design Strategies

Environmental responsibility was central to the project. The studio prioritized reusing the existing structure and finishes while maximizing natural light and ventilation to reduce energy consumption.

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

Exterior Enhancements

The building's entrance features a striking five-metre cantilevered canopy, while the facade has been updated with operable glass sashes to invite airflow. The surrounding landscape has been transformed into a community park complete with layered vegetation and an oversized 3D-printed vase.

Industry Recognition

The Kitaoka Group office headquarters has been shortlisted in the small workplace project category of the Dezeen Awards 2025, placing it among other innovative projects like an experimental whisky lab by Barthélémy Grino and JSa's self-designed studio in a Mexican factory.