Kyūshū (九州, Nine Provinces) or Kyushu is the third-largest island of Japan and most southwesterly of its four main islands. Its alternate ancient names include Kyūkoku (九国 Nine States), Chinzei (鎮西 West of the Pacified Area), and Tsukushi-no-shima (筑紫島 Island of Tsukushi). The historical regional name Saikaidō (西海道 West Sea Circuit) referred to Kyūshū and its surrounding islands.