Sanjo

City, Niigata Prefecture (ken), Honshu, Japan, on the delta of the Shinano-gawa (Shinano River). Sanjo was founded as a castle town in the 16th century. It was a river port and post town during the Tokugawa era (1603–1867), when the city first became known as a centre of metal tool production. Carpenter tools and household hardware are still produced in more than 2,000 small workshops. Pop. (1980) 85,275.