On a rainy day in late March, a group of people were making material to apply to the walls of a two-story concrete house going up in the city of Musashino in Tokyo.

They mixed earth with sand, quicklime, water and chopped straw.

With a trowel in one hand and a small wooden board for the earthen plaster in the other, they applied the material 10 to 15 mm thick on a wide living room wall.