Korea's Goryeo dynasty developed metal movable type more than two centuries before Gutenberg. Historical tradition attributes the first documented use to Choe Yun-ui around 1234, for printing the Sangjeong Gogeum Yemun. The most robust physical proof is the Jikji (1377), the oldest surviving book printed with metal movable type, inscribed on the UNESCO Memory of the World Register in 2001 and held at the Bibliothèque nationale de France. Gutenberg independently reinvented the solution in Europe; his revolution had an incomparably greater cultural impact. But metal movable type, as a technical milestone, belongs to Korea.