Early movable metal types produced by lost-wax casting

The oldest extant movable metal print book is Buljojikjisimcheyojeol (Jikji) [1–9], printed in Korea in 1377. The prevailing assertion has been that the movable metal type used in its printing was made through lost-wax casting [3–6]. Unfortunately, however, there is no record of movable metal type being made from lost-wax casting, and to this day no relics have been found supporting this claim. We report that the first known movable metal types having the features of lost-wax casting are found in the Wibuinja, the movable metal type of the Joseon Dynasty Period that is preserved by the National Museum of Korea. The tapered shape of the body of the movable type and the unevenness of the stripe before casting defects broke out both suggest use of the lost-wax casting method. Although our findings do not conclusively prove that the movable metal type used for Jikji was made through lost-wax casting, the possibility of its production from lost-wax casting cannot be excluded because movable metal types made from lost-wax casting exist.