Mei and the paper noteMei lived in a big city in China, about a thousand years ago. Her father was a merchant who sold silk and tea. People paid with copper coins, each with a square hole, tied together in long strings. Mei's father hung strings of coins on a pole and carried it on his shoulders. Clink, clank! The coins were heavy, and his back ached. "There must be a lighter way to carry money!" said Mei. So merchants left their coins with a shop they trusted. The shop gave back a paper note that said how many coins were left. In the next city, a friend of the shop swapped the note for coins. Later the government printed notes with carved wooden blocks. Each note had a picture and a seal.