The polyhedron house

Also known as the “Reflection of Mineral” house.

The home-owners’ brief for this unique home in Nakano-ku, Tokyo, was a simple, yet functional design that maximized the total living space.

The architect, Yasuhiro Yamashita of Atelier Tekuto, said that the house was not intentionally designed to be abstract or strange. The unusual polyhedron shape was the result of the narrow block and the building codes which limit the height and roof angles that are permissible. To create the most living area, the house has 1 basement and 3 stories above ground. A covered carpark was even included in the design.

The home-owners are very happy with the final product and said that they will never get tired of looking at the 14-sided house.


The house is located in a densely packed residential neighborhood on a corner block of land that is just 44 sqm in size. It faces two roads with widths of 5.15 meters and 3.7 meters. There were two building restrictions which led to the odd shape of the house:

  • Doro Shasen Seigen” (Road slant plane restriction): This is to ensure adequate sunlight into the street. The line starts from the edge of the opposite side of the street and the building can only be built within this angle.
  • Kitagawa Shasen Seigen” (Northern-side slant plane restriction): This is to ensure adequate sunlight to the property on the northern side. This code requires that residential properties have a minimum of four hours of direct sunlight each day. As sunlight is received from the southern side, the code makes sure that your neighbor on the northern-side of your property does not block all of your sunlight.

These regulations are the reason why you see so many buildings in Japan that have slanted or sloping facades from a certain floor and higher.


To create a feeling of more space in the living room on the 2nd floor, floating shelves were used as well as glass tabletops and ‘light’ furnishings. The kitchen counters are also floating, and the rangehood has a mirror finish. The bathroom on the 3rd floor also has a mirror finish on the door which makes the room feel larger. The bedroom in the basement was initially designed to be a storeroom but was later changed to a bedroom. The cupboards are built-in and deep enough to store all clothing as well as suitcase and large luggage.

Building Details

– Land: 44.62 sqm
– House: 86.22 sqm (927 sqft)
– Construction: 3 stories + 1 basement, reinforced concrete
– Planning and design: Yasuhiro Yamashita, Atelier Tekuto



“Sumunara Designers Jyutaku No. 009” Sumai Nikkei.
Atelier Tekuto (