city, Oita ken (prefecture), Kyushu, Japan, facing Saiki Bay. It developed as a castle town on the small delta of the Banjo River during the Muromachi era (1338-1573) and came into the possession of the Mori daimyo family in 1601. Because of its good harbour, Saiki was selected for a base of the Imperial Japanese Navy in 1933. After World War II most of the military facilities were converted to industrial use; ships, paper pulp, and cement are produced. The port has been engaged in foreign trade since the 1950s. Pop. (2005) 80,297.
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