Initial plans called for the
Japanese National Railways (JNR) to build a
spur line linking Atami on the
Tōkaidō Main Line with Shimoda. However, funding was limited in the 1930s due to a combination of a tight
fiscal policy under
Prime Minister Osachi Hamaguchi during the
Great Depression, and a number of technical issues. On March 30, 1935, the initial 8.7 km section of the Itō Line linking Atami with was opened. The second (8.3 km) section from Ajiro to was opened on December 15, 1938. Both sections were electrified at 1500 VDC when opened. Further work was delayed, and then canceled due to the outbreak of
World War II. Construction south of Itō resumed when the private-sector
Tokyu Corporation acquired the rights to complete the line to Shimoda and established the
Izukyū Corporation to manage construction and operations of this section. The line to Shimoda opened in 1961. ==Operation==