 The Kitakyushi Railway was nationalised on 1 October 1937 and JGR, now in control, designated the track from Higashi-Karatsu through Yamamoto to Imari as part of the Chikuhi Line.For many years thereafter, Yamamoto was the only transfer station between the Karatsu and Chikuhi Line.On 22 March 1983, a new route for the Chikuhi Line was opened, with Highashi-Karatsu relocated and a through-track built across the Matsuura River from there via to Karatsu.