 In 1905 a 1.6 km line was built from Otaru - Minami-Otaru to connect the Hokkaido Coal Co owned line to the Hakodate line, and the Government nationalised the Hokkaido Coal Co in 1906.Doubling of the line between Minami-Otaru and Iwamizawa opened 1909-11, and was extended to Sunagawa 1924-26, to Takikawa in 1956 and to Asahikawa 1964-68.The Otaru - Minami-Otaru section was duplicated in 1965.