There's no running around naked in Sosuke Fujimoto's House NA. The 3-D matrix of tiny rooms and exterior terraces—all located on different floor levels—is encased almost entirely with see-through glass. Supported by a bare, white structural frame, the transparent walls reveal the interior contents to all who pass by. Even in Japan, where proximate neighbors and thin walls often compromise privacy, an unclothed house is a daring solution.

Yet House NA is not simply a bold, exhibitionist gesture. It is Fujimoto's carefully considered response to the building's surrounding conditions. Designed for a working couple in their forties, the home is located in a quiet Tokyo neighborhood on a 592-square-foot plot that opens onto a narrow street and is hemmed in by adjacent houses just about everywhere else. It does not turn its back on the city with solid walls, a typical strategy for Japan's cramped urban areas. Instead, the house engages the environment with transparency. Just inches away, a neighbor's concrete-block wall doubles as House NA's wallpaper, while a borrowed view toward the roof garden next door enhances the interior.