Zero Zen Houses is a project of Kyohei Sakaguchi. Sakaguchi trained as an architect but became fascinated by the things people build themselves, especially small shelters that have no utilities, thus no costs, thus "zero yen houses." Sakaguchi photographed many of these. Here's one with his description below:
The owner of this house lives with a dog.
The dog has a room of its own, but the two live in close quarters. This type of house is often seen in Osaka.
Some of the Zero Zen Houses are under highways, like the one in Nagoya below. Sakaguchi titled this one "A Huge Living Room":
This house also uses an elevated highway as a roof.
However, the inhabitant of the space keeps his belongings to a minimum.
The wide space, including the chairs and preexisting waterworks, is used as a living room.