The first experiments using movable type made of clay and later of wood began in China in the 11th century. The use of metal letters is known from 1234 onwards in Korea. The oldest preserved work printed using movable type is the Jikji Simche Yojeol. It contains the collected anthology of Zen Buddhist teachings and was produced in the Heungdeok Temple in Cheongju (South Korea) in 1377 and exists in only one original kept in the Bibliothéque Nationale in Paris. It was printed using letters made of copper in a complex investment casting process. The mould consisted of a moist sand mixture with which the types (male moulds) made of carved wax were surrounded creating an impression (die) in the inside of the form. When heated, the male mould made of wax melted away leaving a hollow space for pouring the metal. When the letter was removed, the mould had to be broken. The metal types were arranged into a set in a wooden container and after being coloured, transferred onto paper by rubbing.

This early type printing method was practiced in and around the royal palaces and continuously improved. However, as it was carried out using the technique of the lost form (the wax moulds melted away), serial production of the same type was not possible. Unlike the worldwide spread of the European technique by Johannes Gutenberg, Korean type printing remained limited to the region in its economic and cultural importance.