Block printing was a costly and time-consuming process, for each carved block could only be used for a specific page of a particular book; besides, a single carving mistake could ruin the whole block. However, movable type printing changed all of that.

In the Song Dynasty (960-1279), a man named Bi Sheng carved individual characters on identical pieces of fine clay. Each movable type had on it one Chinese character which was carved in relief on a small block of moistened clay. After the block had been hardened by fire, the type became hard and durable and could be used anytime and anywhere. The movable type pieces could be glued to an iron plate and easily detached from the plate. Characters could be assembled to print a page and then broken up and redistributed as needed. When the printing was finished, the pieces could be put away for future use.

Movable type printing developed very fast. This technology then spread to Korea, Japan, Vietnam, and Europe, while based on clay type, type made of wood, lead, tin, and copper gradually appeared. Johann Gutenberg of Germany invented movable type printing made of metal in the 1440s.