One is Takasugi-an (which means “too high room”). This is a tea-ceremony room and it was selected as one of the top 10 most dangerous architectures in the world by Time Magazine (top 1 is the Leaning Tower of Pisa). The room is built on two 6-meter high chestnut trees.
I wanted to go inside but didn’t know how people can go in.
The other is Jinchokan Moriya Historical Museum. Two trees are used as pillars and pumping out of its roof!
Fujimori was born in the Suwa area and was a professor at Tokyo Univ until last year. His designs are not only funny but also wonderful because they are made of natural materials like wood and stone and match with the natural surroundings. Its Google Map is here.