The site for this project is nestled at the intersection of two major rivers, the Sumidagawa and the Onagigawa. One side faces the street, while the remaining sides are abutted by the neighboring house and a retaining bulkhead along the Sumidagawa river, which features an esplanade along its length. This is an exceptional situation: between the bulkhead and the road, the house is surrounded by public space on three sides, and therefore a special consideration of the architectural design was to preserve the privacy of the occupants.

The clients are a married couple whose grown children live independently. The house’s living space spans from the third floor to the fifth floor penthouse, and the rooftop includes a pool and a garden. Below, each of three rental units on the ground floor and second floor can be accessed via its own separate entrance, and can be used either as an office or a residence. Unit “A,” designed for use as a gallery space, was placed on the ground to permit easy access from the street.

Soon after beginning this design, certain considerations emerged as focal points. Regarding the function and program of the structure, my design strategy was to allow the program to be modified to reflect changes to the makeup of the household. At one extreme, there was the possibility of the complete reversal of certain elements of the program, for instance granting the residential space the ability to function as an office. While this was not a direct component of the clients’ wishes, it is natural with any kind of building for the function of the program to change with time, and I decided to highlight that aspect of this project as a positive component. Through many meetings, I discerned the client’s desire that the building should be designed to last a long time, regardless of current trends.

The design process for the residence first considered maximum legal limits for height and floor area, and proceeded from the standpoint of maximum volume. Next, within the universal form, the possible function of each floor was considered, as were the constraints on those functions. I designed the interface between interior and exterior to articulate spaces that reflect the public spaces that surround the house: the Sumidagawa river outside, and the street. Finally, I designated certain areas as residential, and inserted the rental units into the layout.

Around the central circulation core, I designed different spaces with exterior surfaces that act as interfaces between inside and outside — the solid wall surface and the translucent wall surface, which are closed, then an opening which encompasses three directions, and the roof space and terrace. As you proceed upward to successive levels of the house, the space becomes more and more open to the outside. Additionally, in consideration of possible future functional modifications, the air conditioning system and plumbing equipment were installed so as to be easily accessible for retrofitting at any time, and were concealed behind a wooden louver that partially wraps the third and fourth floor, creating a double skin. As the external element of this double skin, the wooden louver fronts the Japanese room on the third floor, folding open or closed as desired. As a result, the folding louver changes the relationship between the space of the Japanese room and the Sumidagawa river flowing by outside.

Even after construction began, I repeatedly re-examined the entire program and composition of the blocks that comprise the house and made some small modifications to the design. This was made possible by designing in accordance with the idea that “the present moment” should always be merely one element of a construction process that can shift or change at any given time. Similarly, concerns about materials and thresholds are likewise a result of continuing to grope toward the best solution at “the present moment” of the design with its specific circumstance, taking into account the movement of pedestrians and other traffic around the site.

Given the maximum permitted volume for the site and in light of the design’s most important determining aspect, namely the connection between the internal space and the exterior envelope, the logical conclusion would be that the building should be visible, like a boat anchored in the Sumidagawa river. It’s surprising that I reached the results that I did through a design process that really only appears logical. You can never know completely what will happen during construction, but must instead accept a type of whimsy bordering on the divine.