Choe Yun-ui Invents First Metal Moveable Type

At first, one cuts letters in beech wood. One fills a trough level with fine sandy [clay] of the reed-growing seashore. Wood-cut letters are pressed into the sand, then the impressions become negative and form letters [molds]. At this step, placing one trough together with another, one pours the molten bronze down into an opening. The fluid flows in, filling these negative molds, one by one becoming type. Lastly, one scrapes and files off the irregularities, and piles them up to be arranged.”

— Song Hyon