Smallest main island (pop., 2004 est.: 4,111,000) of Japan. It is located south of Honshu and east of Kyushu. Much of its 7,065 sq mi (18,298 sq km) is mountainous, and the population is concentrated in urban areas along the coast. Rice, barley, wheat, and mandarin oranges are among the island's major crops. Industries include petroleum refining, textiles, paper, and fishing.