This project is a new Tokyo branch office for Ishida, a long-established manufacturer of scales headquartered in Kyoto, the ancient capital of Japan. The site is surrounded by high-rise condominiums, a national highway, and an expressway, but the road to the east is an important local street that connects the Shin-Itabashi subway station and JR Itabashi station, constantly crowded with people day and night. The east side of the building was considered an interface with the city, where the activity inside would subtly spill out, adding liveliness to the cityscape. At the foot of the building, the focus was to create a community promenade by improving the quality of the street space.

The building's characteristic stepped appearance is a direct visualization of the atrium spaces above the stairs that connect the offices from the third to sixth floors while keeping with the height restrictions. The exterior is composed of polished precast concrete (PC) slabs, aluminum cut panels, extruded cement slabs, and aluminum sashes, carefully designed so that the shift in materials happens at the joints. The entrance space is surrounded by a row of solid polished prestressed concrete columns, creating a soft boundary with the city while integrating the outside space. The light and shadow pattern created by the colonnade in the morning colors the beginning of the day, and at dusk, the soft light enriches the expression of the city. On the upper floors, the colonnade contains a staircase-like diagonal atrium space, creating a workspace where people can move, and the wind can blow through.

A comfortable workplace - In contrast to the stoic, minimalist exterior that embodies the client company's cutting-edge technology, the interior space focuses on worker comfort. We proposed a work style in which workers can freely choose between two zones: an open "white" workplace with high ceilings and a "wooden" zone with low ceilings and a calm atmosphere. The "white" zone is a space that makes the most of the 4-meter floor height by exposing the building frame. The simple ceiling, consisting of steel beams set at 3,600 mm pitch, painted with white fireproof paint and finished with a white deck, was designed as an abstract light-reflecting surface. Visible equipment was minimized, with the aim of creating a calm and focused space where people can feel only indirect, soft light. No light sources penetrate the eye, and no reflections can be seen on computer screens. Conditioned air and naturally ventilated outside airflow along the ceiling surface create a comfortable environment without being perceptible. This was realized based on a repetition of environmental simulations at the planning stage, careful fine-tuning on-site, and further adjustments based on post-completion measurements.

The "wood" zone, on the other hand, is a communication-oriented space with a low ceiling height, designed to create a human-scale space with a low center of gravity. The furniture layout and lighting arrangement can be easily and freely changed. The diagonal atrium and staircase connect the 3rd, 4th, and 5th office floors with the showroom/hall on the 6th floor and are intended to activate communication between the floors. Natural ventilation and lighting allow winds to flow through and natural light to flood the space so that workers can feel the passing time and atmosphere of the city while they work.

We hope that the "white" and "wooden" zones will reflect the diverse work styles of the client's various departments and individuals and stimulate their daily activities.

A diversity of interior environments was achieved by creatively combining inexpensive, general-purpose technologies and natural elements. With activity-based working gaining popularity, the variable indoor environment was accepted as an attractive feature that improves comfort, health, and energy conservation. The actual energy performance value is 61% above standard, achieving "ZEB ready" operational performance.

The air conditioning system is a one-way ductless system using the Coanda effect and floor suction, and the plan allows switching between radiant and convection modes at every 10.8 m span. A high-ceiling space with no vertical temperature difference and no draft was realized to improve ventilation efficiency and reduce the risk of airborne virus transmission. Natural ventilation was introduced by using the vaulted space as a gravity ventilation pathway, and natural resources were actively incorporated through features like natural top lights and rainwater utilization.

A bright and glare-free environment was achieved through the exclusive use of indirect lighting in the form of beams. Power consumption of 6.5 W/m2 is achieved while maintaining an illuminance of 600 lx on the desk surface, and energy is saved by controlled daylight usage.