Gunsan or Kunsan (gŏŏn´sän´), Jap. Gunzan, city (1995 pop. 266,517), North Jeolla (Cholla) prov., SW South Korea, on the Yellow Sea (or West Sea) at the Geum (Kum) River estuary. It is a major port, especially for rice shipments, and is a commercial center for the rice grown in the Geum basin. Rice processing, fishing, and shipbuilding are important industries, and paper, lumber, rubber, and plastic are also produced. The city is also an important railroad hub. Originally a poor fishing village, Gunsan gained importance with the development of its port, which was opened to foreign trade in 1899. The Japanese, who ruled Korea from 1905 to 1945, further developed the city and port.