AR Awards for Emerging Architecture	Commended	December 2007
TNA	House	Karuizawa, Japan
Ring House by young duo TNA (Makoto Takei and Chie Nabeshima) is a unique commission for an emerging Japanese architect. Built for a speculative developer on an expansive suburban site, rather than for a private client on a tight urban plot, it took the architects in a completely new direction, while allowing them to extend their principal preoccupation of how context informs the composition of a wall. Their urban projects (they already have at least four distinguished houses under their belt) tend to exploit specifics of orientation, perhaps most flamboyantly expressed in Mosaic House (AR August 2007) that mimicked phototropism to exploit high-level daylight. Here, one hour from central Tokyo by bullet train, the relative expanse of the 1400sqm wooded site set them new challenges: how to design a house in the round. With a plot ratio of less than 3 per cent, compared with 50-60 per cent of urban sites, the first key decision was where to place the dwelling. While initially daunted by the challenge, very soon clues began to emerge. As a left-over plot bound by two roads, minimum distance enforcements limited the possibilities, as did the site ecology with drainage and the position of trees as contributing factors. Eventually a residual zone was identified, and at the highest point within this area a plot was established set tangentially to the steep contours. Arranging accommodation over three levels allowed the architects to exploit the occupant’s relationship with the trees, which in turn led them to divide the envelope into a series of rings, alternating bands of solid and void. This not only served to slice up the view into two or three ribbon-like compositions per floor, but from the outside serves to shift the viewer’s perception of scale, disguising floor levels to help create a single unified composition. Clad in vertical panels of burnt cedar, the height of successive bands shifts from level to level, neatly integrating internal utilities – kitchen counters, fireplace and sunken bath – culminating in two narrow bands that form an open parapet for the level four roof terrace. All of the levels are connected by a single corner stair, and the house is entered at first floor level across a bridge. Within this contextual framework, the architect applied mature rigour to the spatial and tectonic order of the house, basing the 5.4m square floor plans on the 900 x 1800mm module of the tatami mat and enveloping this grid with two clearly articulated perimeter zones for structure and cladding. In reality, structure and cladding came to site united, prefabricated in composite T-section units with the 120mm square columns and horizontal spandrels craned into place with precision and efficiency. Clearly the AR jury was impressed by this delightful house, and by the architect’s impressive ability to maintain clarity from concept through to completion. R. G. Architect TNA Architects, Tokyo Structural engineer Akira Suzuki/ASA Photographs 2,3 Edmund Sumner/VIEW Email mail@tna-arch.com