Japanese firm Apollo Architects liked the home they designed for a family in Aoyama, Tokyo so much, they decided to move their offices into its basement. Conceived as a multi-use space from the outset so that the owners could earn an income from rent, the complex is spread over four floors with offices in the basement and living quarters on the ground, first and second floors.

Located in a quiet cul-de-sac, the building is unobtrusive from the street, with a subtle facade that's split into three rectangular slabs – one half reinforced concrete, one quarter Japanese cedar-clad louvres and another half-mirror glass. With its own separate access from the street, the basement office is found via an open tread staircase that wraps two sides of a generous lightwell. With two floor-to-ceiling windows that maximise on daylight, the basement now serves as Apollo's HQ which incorporates a small showroom space with furniture samples.

Upstairs, a central dog-leg stairwell wrapped with glass panels punctuates the three floors of the building and channels daylight into the centre of the home. With its huge glass windows, the ground floor functions as a dual-aspect meeting room that’s available for hire. From here, the central staircase leads upwards to the first floor where the main bedroom – which benefits from south-facing, leafy courtyard views, a walk-in-closet and its own triangular balcony – is located. Two further bedrooms and a compact bathroom and wash room overlook the street.

On the second floor, an open-plan living room and kitchen are placed to the west, while a dining area and library are on the east, loosely divided by the staircase. Up above, on the timber-decked rooftop, the family enjoy an 'outdoor living room' area that offers up panoramic views of the neighbourhood.