Interactive floor plan: Division House, Nagano

Enter the forest of Suwa in Nagano Prefecture and you feel immediately lost, even though it's only five minutes from a busy motorway. The site of a new residential project designed by Takei Nabeshima Architects (TNA), this dense wood of Japanese white birches has few points of reference. When the architects, Makoto Takei and Chie Nabeshima, first visited they could only distinguish a pond, a creek and a spring well. 'The endlessness of the forest and the lack of any signposts upset our sense of direction,' says Nabeshima. 'Only the slightly sloping ground told us we were at the foot of the Yatsugatake mountains.'

To bring a point of reference to the thick undergrowth, TNA approached the design of the building as if it were a signpost in itself. And, from above, the asymmetrical pitched roof looks like an enormous arrow, turning the house into a kind of compass.

Built as a weekend house for a couple from Tokyo, the building is arranged along a north-south axis. The main component, which contains a kitchen, living area, bedroom and sun room, is a large cube; a small adjoining cube houses an annex. At ground level, the walls are placed to orientate the views into four distinct zones: the pond, the creek, the spring well and the entrance road. Four cross-shaped walls partition the main building and its annex in a similar way as the exterior walls divide the forest.

'The structure, the walls, the furniture and the window sashes are all made of wood,' says Takei. 'You experience a total immersion in the forest when you are inside the house.' Rather than a building that simply pushes the forest away, Division House creates spaces in-between the trees. 'The house defines the forest into small and close distances, big rooms and small rooms, this forest and that forest,' says Nabeshima.