Matsuyama (mätsŏyäˈmä) [key], city (1990 pop. 443,322), capital of Ehime prefecture, NW Shikoku, Japan, a port on the Inland Sea. It is an important agricultural distribution point and fishing port. Cotton textiles, paper products, petrochemicals, and machinery are manufactured, and mandarin oranges are cultivated. Its feudal castle (built 1603), one of the best preserved in Japan, stands in a magnificent park.