The features of Shitoro Yaki stem from its utilisation of soil from the Kanaya region in Shizuoka prefecture. Soil from the Kanaya region is naturally hard, rendering Shitoro-ware very firm and moisture resistant after baking. Unglazed Shitoro-ware is often dark brown or dark yellow in colour. Materials from the Kanaya region also afford Shitoro Yaki its distinctive glaze colours; a natural and iron-rich substance called Niishi gives the pottery a deep red colour. Shitoro Yaki gained notoriety after a kiln in Shimada City, producing Shitoro-ware, was named by Kobori Enshu (famed seventeenth century tea master) as one of the great “Seven Kilns of Enshu”.