Even in the later Sanyo Shinkansen and Tohoku Shinkansen line, the routes are rather mountainous compared with those in France and Germany, being provided with many obstacles, such as undulations and curves, which have prevented high-speed designs.
より新しい山陽新幹線・東北新幹線などもフランスやドイツなどと比較すると山岳区間が多く、路線の起伏やカーブの設計などにおいて高速化を妨げる点が多い。