A "Kanumatsuchi" is a type of soil for bonsai, which is a very light and porous rock of volcanic andesite quality. It is a substance that erupted from the central crater of Mt. Akagi in Gunma Prefecture, Japan, and is found in areas from Tochigi Prefecture to the seashore of Ibaraki Prefecture. The name Kanumatsuchi comes from Kanuma, a region where thick layers of this rock are found. Kanumatsuchi has many capillary holes on the surface of the grains, which make it excellent for air permeability and drainage capabilities. It is suitable for bonsai plants that prefer acidic soil, such as azaleas and camellias.