Modern Japanese architecture is noted for innovation. But even in such a cultural climate, this concrete hilltop home in Tokyo is a daring departure from the conventional in concept and materials. It is a 33-foot hollow concrete cube supported by four short, sturdy pillars and is entered through a cylindrical core which rises to the top of the structure. The circular windows are perhaps the most distinguishing feature 25 of them arranged symmetrically on each of the four walls and shaded from the sun by tubular concrete awnings.
The three floors are cantilevered from the central core and seem to float between the bottom and the top of the spacious cube. The design permits openings around the inside perimeter, so that a visitor can look to the ceiling 30 feet above. There are virtually no partitions in the eight-room residence except for those enclosing the bathroom and the kitchen. The building demonstrates the versatility of concrete in structure and in decoration. Lightweight concrete made with expanded shale aggregate was used in the structure, which reduced dead load and supplied thermal insulating qualities. A water-reducing, set-controlling admixture helped the concrete to attain both high early and high ultimate strengths, improved the placement and workability of the mixes, facilitated the finishing, and reduced significantly the incidence of shrinkage cracking.
The concrete walls are surfaced on the outside by concrete tiles. These tiles have circular projections painted red on one side and blue on the other so that the hue changes as the observer changes perspective. To the building trades, this spectacular residence represents another great performance in concrete.