Chinese engineer who in 984 built the world's first canal lock. Assigned to the enormous building project of the Grand Canal connecting the Yangtze and Yellow rivers, Ch'iao Wei-Yo devised a system that made use of a chamber enclosed by movable gates between two stretches of water differing in height. Water either entered through sluices to raise the boat, or was drained to lower the boat to the appropriate level. Despite this early invention of the canal lock in China, the invention gained little use there. Instead, it became much more widely implemented in the West, where it first appeared in 1396.