The Yu Yi or Longevity Lock is a lock-shaped ornament which a baby always wears on its neck or hand. Tracing back to the han Dynasty (206BC - 220AD) as the longevity thread, it is said that wearing it could bring good health and good luck to the child as the lock could ward off evil.
The custom changed during the Ming Dynasty as adults adorned themselves with the ornament for good health and longevity. Gradually, the longevity thread developed into the longevity lock.
Today, children wearing the Longevity Locks are believed to have good luck and a bright future ahead.