rough wall plaster; cob
A traditional Japanese wall-building material made of clay mixed with straw and other fibers, used as a rough undercoat before finer plaster layers. The term is specific to traditional architecture and construction.
See also: 中塗り土
Rough wall plaster is used in the walls of old traditional houses.
After applying the rough undercoat, they finish with a middle coat of plaster.
Compound of 荒 (rough) + 壁 (wall) + 土 (earth, soil). The term directly describes the material's use as a rough earthen wall coating.