The construction of the new tunnel started as a project to connect Honshu and Kyushu with a high-speed railway. The tunnel was constructed at the shortest section in the Kanmon Strait between Dannoura, Shimonoseki City - Mekari, Mojiku, Kitakyushu. Although the entire Shin-Kanmon Tunnel is 5 times longer, the undersea section is shorter than conventional line Kanmon Tunnel (Kanmon Tunnel undersea bed section is long).
