The Koreans were using wooden types embedded in wax in shallow wooden trays to make a printing surface during the 14th century. In 1397, the King of Korea set up a foundry to produce metal types. When in use the types were wedged into place with narrow strips of bamboo between each vertical row. The printing was done by inking the type and taking an impresion on the paper by gently rubbing on the back. These movable types antedate Gutenberg's invention of movable type in Western Europe by more than a century.
© Science Museum / Science & Society Picture Library