Potter Mariko Harada uses clay from the Kajiki region of the Kagoshima prefecure.
Series 1015 comes in two types of blend of clays: 10% and 15%. 10% is a blend of KAJIKI clay and white SHIGARAKI clay and 15% is a blend of KAJIKI clay and red SHIGARAKI clay.
The KAJIKI clay is rich in iron and it creates unique and rich looking pottery. This clay can be found only in this region.