For a utilization of partially completed tracks of the Shinkansen, JR East and Keisei lines to  were realized. A much faster line had long been needed, and for that purpose the first priority was the Keisei – Hokusō route.
The implementation of partially completed Shinkansen tracks between JR East and Keisei lines was achieved. There had been a long-standing demand for a much faster line, which led to the Keisei – Hokusō route being given first priority.