Grooves on the edges of coins appeared in the early 16th century. At that time, people would often cut off small amounts of precious metal from coins to sell, and then they’d pass on the damaged coins at full value. To counter this practice, a special process known as reeding was introduced. It consisted of carving a series of grooves on the edges of coins so that it would be easy to see if a coin had been tampered with. Hardly anyone clips coins nowadays, but reeding remains a long-standing tradition.