Our second recent story from Japanese architects Studio Velocity is a house shaped like a fairytale tower with five different staircases connecting its two floors (+ slideshow).

House in Chiharada was designed by Studio Velocity in the garden of another residence in Japan's Aichi Prefecture, so architects Miho Iwatsuki and Kentaro Kunhura specified a cylindrical volume that would contrast with the rectilinear structure of the existing building.

"To avoid facing each other, a round-shaped volume was chosen against the corner of the square-shaped volume of the main house," explained Iwatsuki.

The first of the five staircases wraps the curved perimeter of the house, leading up to a first-floor entrance that is sheltered beneath an ultra-thin canopy.

Inside, a large circular room occupies the entire floor and contains a sequence of family spaces that are divided by four box-shaped volumes with various proportions.

Each box contains a staircase down to a different room on the floor below. Arched wooden doors lead inside, while square windows help to draw in extra light.

One staircase descends into the bath and washrooms, while the other three head directly into bedrooms. There are no corridors between these rooms, but extra doors give direct access to the bathroom from the other rooms.

"By intersecting the living space from exterior to interior and from upstairs to downstairs, the hierarchy between the first floor and the second floor disappears and individual functions and sceneries mix together," said Iwatsuki.

To allow this arrangement to work, the architects gave low ceilings to the ground floor so that each staircase needed only ten treads. Meanwhile, the upper level is a double-height space that brings light in through openings in the roof.

Additional doors allow residents to open their bedrooms out to the garden.

Studio Velocity also recently completed a house with a squashed diamond shape designed to maximise space without overlooking the neighbours.

Other Japanese houses on Dezeen lately include a residence where furniture forms sections of staircases and a home with a tunnel-like entrance and faceted interior walls. See more houses in Japan »

Photography is by Kentaro Kurihara.

Here's a project description from Studio Velocity:

House in Chiharada

Deconstruction of a multi-floored architecture

A site with a two-storey main house is split in half and a new house for a young couple is going to be built on the vacant area.

Although there is enough space within the surrounding environment and there are no approximate buildings, it is inevitable that the new house be built rather close to the main house. In addition, a multi-floor living space was needed due to the limitation of the site area.

Therefore, to avoid facing each other, a round-shaped volume was chosen against the corner of the square shaped volume of the main house. It was arranged so as to create a valley-like space in between the two buildings spreading open towards the outside. The round shape is set on an irregular shaped site, creating various shaped gardens around it that can be shared with the main house. Each room on the first floor in the round-shaped building has a door that opens to the gardens.

A number of small rooms and a bathroom are located on the first floor, and a single large hall where everyone can gather is arranged on the second floor. Downstairs and upstairs are relatively close by lowering the height of the slab (the upstairs floor) that lies between the two floors, and therefore, the garden grounds can be seen even from the centre of the second floor through the enclosed staircases and downstairs rooms.

Entering through the entrance on the second floor, enclosed staircases are arranged within the living room that is filled with natural light from a high ceiling; the enclosed staircases look like slender structures of various heights. The space seems like being on a street in a town, and makes you feel that it is on the ground level although it is upstairs of the multi-floor building.

Each of the four enclosed staircases connects to an individual room on the first floor. When you look up at the open ceilings from the children's room or the bedroom (inside of the enclosed staircases) that almost reach the roof, the sky can be seen and natural light pours down from skylights above the openings in the enclosed staircases. It was intended with this house that a person be able to feel the ground and sky throughout, though it is a multi-floored building.

Elimination of the discontinuity between multi-floor stairs that usually exists might result in the unfolding of a united and continuous new living environment. By interrelating with each area, including the outside, and by intersecting the living space from exterior to interior and from upstairs to downstairs, the hierarchy between the first floor and the second floor disappears and individual functions and sceneries mix together.

Location: Chiharada, Okazaki-city, Aichi, Japan
Site Area: 144.93 sqm
Built Area: 55.28 sqm
Total Floor Area: 110.56 sqm