The clients for this small house in Tokushima, Japan, asked architect Naoko Horibe for a timber interior and an exterior that looks like a sports car.

Naoko Horibe of Osaka studio Horibe Associates says she designed the house to "combine two completely opposing concepts in a single structure, without a sense of clashing."

"One was an exterior like a sports car; the second was a natural interior featuring wood," she said.

A cloak of galvanised metal folds over the sides and roof of the structure, forming an asymmetric shape with a streamlined appearance.

This layer of cladding overhangs both the front and rear of the building, creating a sheltered entrance and shading the house's windows.

The interior centres around a combined living and dining area, which leads directly into every other room and removes the need for corridors.

Timber roof joists are left exposed across the ceilings, plus the pitch of the roof creates a pair of triangular windows along the upper sections of the walls.

The angled roof also allows space for a small loft, which the architect describes as a "special den" for the family's husband.

A bedroom and traditional Japanese room run along one side of the house and are slightly elevated to create storage spaces underneath.

Photography is by Kaori Ichikawa.

Key to diagrams:

1.Approach
2.Entrance
3.Living, dining and kitchen
4.Food storage
5.Terrace
6.Japanese-style room
7.Bedroom
8.Walk-in closet
9.Lavatory
10.Washroom
11.Bathroom
12.Closet
13.Loft