data seto japanSeto, city, Aichi ken (prefecture), central Honshu, Japan, northeast of Nagoya. Seto, established about 1230, is known for its porcelain (Seto ware). Since the Meiji period (1868–1912),Seto (, Seto-shi) is a city in Aichi Prefecture, Japan. As of 1 October 2019 , the city had an estimated population of 127,659 in 56,573 households, and a population density of 1,146 persons per km . The total area was 111.40 square kilometres (43.01 sq mi).