Printing books by making and combining types has played a major role in the dissemination of knowledge by enabling the rapid delivery of various information. Among them, metal types made of materials such as copper and lead require a variety of techniques for printing, such as printing ink manufacturing and papermaking, as well as casting of type. Goryeo produced the world's first metal type, proving its technical prowess. The type was excavated from a Goryeo Dynasty tomb in the area of Gaeseong during the Japanese colonial period. Unlike the Joseon Dynasty type, the back of the type is not even and has an oval shape, which seems to be intended to make it easier to hold the type with wax.