 In 1916 the Awa Electric Railway opened a line from Nakahara to Naruto, including the Yoshinari to Ikenotani section, which is now part of the Kotoku Line.The Takamatsu to Hikida section was opened between 1925-28 by the (then) Japanese Imperial Railways.In 1933 the Awa Electric Railway was nationalised, and in 1935 the Hikida to Ikenotani and Yoshinari to Sako sections were opened, completing the line.