Kyushu. Kyushu (B, Kyūshū, literally nine provinces) is Japan's third largest island, located southwest of the main island Honshu. An early center of Japanese civilization, Kyushu offers many historic treasures, modern cities and natural beauty.yushu. Kyushu (B, Kyūshū, literally nine provinces) is Japan's third largest island, located southwest of the main island Honshu. An early center of Japanese civilization, Kyushu offers many historic treasures, modern cities and natural beauty.