Black Monolithic Wall

This custom residence was designed for a parent and child on a quiet residential site relatively close to central Tokyo. The site is an extremely narrow flag lot, with a street frontage of less than two meters. The project transforms these severe spatial constraints, together with Japan’s stringent height and setback regulations, into the driving force for a dynamic architectural experience unique to this elongated site.
The central concept is the Black Monolithic Wall—a continuous, sculptural boundary wall extending deep into the flag-shaped site. Rather than functioning merely as a fence, the wall becomes an integral part of the architecture. Finished entirely in black, it appears as a single monolithic form while incorporating the staircase, meter boxes, mailbox, lighting, handrails, and other necessary functions. Beginning at the narrow street frontage, it defines the long approach and gradually leads visitors toward the entrance on the second floor. The cantilevered black staircase emerges from the wall as part of the same solid composition, turning the act of entering the house into a dramatic spatial sequence. Light and shadow moving across its textured surface continuously alter its expression throughout the day.
The residence consists of three interconnected levels. To maximize the interior volume while complying with height restrictions, half of the first floor is embedded below ground level. This semi-basement accommodates the private spaces, including the principal bedroom, studio, and bathroom. The second floor contains guest rooms and serves as an intermediate, semi-public layer, while the third floor accommodates the dining and living areas. A central void visually and spatially connects the second floor with the dining area above, creating a sense of openness within the narrow building.
The bathroom features a jetted bathtub facing a tsubo-niwa, a small Japanese courtyard garden, through which soft natural light enters the interior. A shoulder-width overhead shower provides a deeply relaxing bathing experience. The tsubo-niwa also functions as a light well, drawing daylight and air through the different levels. In contrast to the powerful black monolithic exterior, light, greenery, and the vertical void create a calm and comfortable living environment within.