Japanese studio FORM/Kouichi Kimura Architects has completed a family house in Shiga, Japan, that is 27 metres long but only 2.7 metres wide (+ slideshow).

Faced with an extremely long and narrow site, architect Kouichi Kimura designed both floors of the two-storey Promenade House with a simple layout, where sequences of rooms are connected by long corridors.

Most rooms open out to a corridor, making use of all available space. "As you proceed along the hallway you will see the spaces spread out, one after another," said the architect.

A kitchen, dining area and living room occupy one space on the ground floor and feature windows that line the edges of the floor.

Steps at the back lead to a raised double-height study with a large rear window and a skylight overhead. A ladder leads from the study to the floor above, although residents can also use a staircase at the front of the house.

The corridor on the upper floor is divided in two. Silver curtains screen bedrooms and storages areas at one end, while the bathrooms are surrounded by turquoise walls, intended to give "an impression of cleanliness".

Another double-height room is also contained on this floor and brings in light through clerestory windows. The architects refer to this space as a balcony, even though it's completely enclosed by exterior walls.

Several polished concrete surfaces crop up though the building, while the floor in the living room is built from wood.

Kouichi Kimura set up his studio in Shiga in 1991. Other residential projects by the architect include House of Representation, which features a large light chimney, and House of Silence, designed to be deliberately alien to its neighbours.

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Photography is by Takumi Ota.

Read on for a project description from the architects:

Promenade House

The project is for the house owned by a young couple and is planned at the unique site 4 metres wide and 35 metres deep.

The geometrical restriction of the site is reflected in the internal composition of the house. The building, with a width of 2.7 metres and a total length of 27 metres, is laid out in accordance with the narrow site to draw its outline.

The internal space has been planned to have a long narrow hallway, with which your body senses the site geometry. As you proceed along the hallway you will see the spaces spread out one after another.

The long hallway is extended from the entrance on the first floor, led by the footlight through the dining and living rooms, and connected to the raised study at the very end. It reaches to the idyllic view seen through the large opening of the study where the tapered line of sight from the entrance is opened up.

On the second floor, two hallways are planned to be extended from the staircase that has a top light. One has a green wall aiming for colour effect. The vivid green hallway surrounds the balcony, giving an impression of cleanliness to the adjacent bathroom and washroom.

The other is connected from the kid room through the bed room to the bridge at the open-ceiling space. It is designed to control light; the light through the light transmissive curtain separating the kid room, or the sunlight from the high-side light in the open ceiling space leads you forward.

The end of the hallway becomes a bridge, and the ladder installed there connects the upper and lower spaces to produce continuity.

The green wall is used at both ends of the building, providing more impressiveness of the total length. The hallways laid out in this house are the promenades that strongly impress the site geometry.

Architects: FORM/Kouichi Kimura Architects
Location: Shiga, Japan
Client: Private

Construction Year: 2013
Site Area: 166,08 sqm
Constructed Area: 124,3 sqm