This white porcelain implement used for preparing medicinal products consists of an oval mortar and a pestle designed to pulverize herbs by rolling over them in the mortar. In China, implements of this type are called a yaochuan (“medicine boat”) due the shape of the mortar, while in Korea the term yagyeon (“medicine pestle”) is preferred. The pestle in this example takes the form of a disk with a diamond-shaped cross-section containing a hole at the center through which a shaft is inserted to grind medicinal ingredients by rolling it in both hands.