Nendo Designs a House in Japan with Stairs Running Through It

The two met in school and have been friends ever since and partners ever since Sato established his design studio Nendo in 1997.
It was roughly 3 years ago when Ito went to Sato with the official request.
For one, the home needed to house 2 familes: his own and his in-laws.
The home is being called Kaidannoie, which means house of stairs.
(photos by Takumi Ota)The parents living quarters (above) and another, more functional staircase (below) that extends through the house.