Nearly all Japanese structures use wallpaper rather than paint.
The reasons being the high susceptibility of cracking and the easy coverage and cleaning of wallpaper.
We prefer to use paint, so were interested in what natural options are available in Japan. Yoko came across a company which distributes a German product called Kreidezeit. It comes as a powder which is mixed with water, the price is very reasonable. So we contacted the representative in Japan. She came to Okayama and showed us how to mix the paint and we tested it out.
Once mixed it should have the consistency of 'melted ice-cream'.
I'm worried about doing all the plastering work and painting myself, and hope that no cracks will develop...Otherwise it will be wallpaper time!