 As a result, a subway line was planned to interface with the existing rail network.In the 10th report of the Transport Policy Committee in 1989, the plan was listed as a "line that should be considered for future construction" between Kami-Shinjō and Yuzato Rokuchōme.Later on, as underground obstructions were discovered along the planned route, the starting point was changed in 1996 from Kami-Shinjō to Itakano, where the population was increasing due to residential development.