The Kanmon Tunnel is an undersea tunnel crossing the Kanmon Straits between Shimonoseki, Yamaguchi, and Kitakyushu, Fukuoka in western Japan。 When opened in 1942, the railway tunnel provided the first direct link between Honshu and Kyushu, two of Japan's four main islands.
The Kanmon Roadway Tunnel carries National Route 2 under the Kanmon Straits。 It opened in march 1958.
