The 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 (, which contributed "Kan" to the name of the strait) and on the
Kyushu side is
Kitakyushu, whose former city and present ward,
Moji , gave the strait its "mon" . The straits silt up at the rate of about 15 centimetres per annum, and dredging has made it possible to build the
New Kitakyushu Airport at low cost.