Kyūshū, island of Japan, the most southerly of the four major Japanese islands. It is separated from the island of Honshū by Kammon Strait and from Shikoku by Bungo Strait. Kyūshū is an irregularly shaped, mountainous island. The coalfields in the north once provided about half the coal mined in Japan, but yields have decreased. The principal crops are rice, tea, tobacco, and citrus. Fukuoka is the largest city and Kitakyūshū is the major industrial center of the island. Other important cities are Kumamoto, Kagoshima, Ōita, Miyazaki, and Saga, all prefectural capitals, and Sasebo, site of a naval base. Area, 36,554 sq km (14,114 sq mi).