Window on the city.

Kazuyo Sejima was faced, in her commission for the Y House, with the familiar Japanese urban conundrum of varying the relationship between interior and exterior, intimate and shared domestic space, the world beyond and the plot itself.

To arrive at some sense of enclosure, Sejima has parceled off garden space in exactly equal measure to either end of the site, and has put the house fair and square in the centre of the plot. Each garden is white, a walled enclave with a few trees.

The house is approached up steps -- either by a flight of narrow white stairs leading from the garden directly on to a substantial balcony or up a flight of steps directly to the door into the first floor living room. This is clear double-height space, its side walls almost entirely clear-glazed, with the option of subdivision by a series of corrugated clear plastic folding screens.

The only solid and sizeable intruder into this space is a second floor guest room, reached by spiral staircase. In contrast, the ground floor is strongly compartmentalised and even includes a traditional tatami room within the master bedroom. The structure of the house is rigid frame construction, a brittle hard table sheltering the frame and its fragile contents. On the street front, the house is skinned in stone, a black slab broken up by the diagonal journey taken by the entrance steps. Otherwise, floor-to-ceiling glazing offers the house on full view to its neighbours.

Here, to European eyes, is a curious phenomenon. Apparently in defiance of the drab surrounding environment, a younger generation of architects is boldly designing houses that seem to defy the notions of Japanese domestic privacy and self-effacement and emblazon themselves on the city scene.

Sejima's Y-house, even with its two-walled gardens, seeks to confront the outside world. The exterior scene is embraced by the interior, the interior by the exterior. There are moments of retreat; the tatami room, the guest room above, but effectively no escape. Sejima has the courage of her convictions; will her clients be able, comfortably, to sustain them?