Operation Ten-Go (天号作戦, Ten-gō Sakusen), also known as Operation Heaven One (or Ten-ichi-gō 天一号), was the last major Japanese naval operation in the Pacific Theater of World War II. The resulting engagement is also known as the Battle of the East China Sea. The battle demonstrated U.S. air supremacy in the Asiatic-Pacific Theater and the vulnerability of surface ships without air cover to aerial attack. The battle also exhibited Japan's willingness to make extreme sacrifices in kamikaze attacks aimed at slowing the Allied advance on the Japanese home islands.