Since its construction in 1959, Kitano Construction's former Nagano headquarters has undergone a series of expansions designed by Dr. Junzo Yoshimura to accommodate the expansion of the company's business, but parts of the building had deteriorated significantly and a reconstruction plan was urgently needed.

The adjacent land to the south, which was acquired prior to the project, faced a roadway that divided the site, so modifications to the existing roadway were considered from the standpoint of development permits. After discussing solutions that would expand the design possibilities, it was decided to abandon a portion of the narrow street and replace it with another road that could be passed through in an L-shape to avoid obstructing the flow line.

In order to maximize the standard floor area, the new headquarters building was designed to be rotated 90° from the old building, with the skyline ratio relaxed against the diagonal restrictions of the road and adjacent land. In order to minimize the external volume of the building, the building was set back 8 meters to the road on the north side, creating an open space in the area and renewing the urban landscape of this urban district. White granite with a distinctive light gray stripe pattern was used throughout the exterior, creating a design that contrasts with the building.

In addition to the consideration and contribution to the surrounding community, the building's seismic isolation structure was adopted as a BCP (Business Continuity Plan) measure in the event of a disaster, which was another issue to be addressed. This structure has reduced the weight of the upper steel frame and realized a column-free space of approximately 13 meters. In addition, environmental facilities utilizing natural energy, such as a geothermal hot-and-chilled water radiant air conditioning system and solar panels, have been proactively introduced.

In the relocation of the tea ceremony room “Gan-un-an,” we devised a space for introduction while preserving the rich spatiality created by Dr. Junzo Yoshimura. For example, the repositioning of the hand basin and stepping stones, the black plaster walls of the dew path, and the design of the earthen floor and ceiling lighting were carefully designed to meet the legal requirements while not compromising the spirituality of the tea ceremony room.

Some of the interior design elements, such as the entrance hall and reception room, were done in collaboration with Norm Architects (Denmark).