The Kanmon Straits (関門海峡, Kanmon-kaikyō) or the Straits of Shimonoseki is the stretch of water separating two of Japan's four main islands. On the Honshu side of the water is Shimonoseki (下関, which contributed "Kan" (関) to the name of the strait) and on the Kyushu side is Kitakyushu, whose former city and present ward, Moji (門司), gave the strait its "mon" (門).