Yamagata Shinkansen
The first mini-shinkansen route to be built was the Yamagata Shinkansen, converted from the 87.1 km section of the Ōu Main Line between Fukushima on the Tohoku Shinkansen and Yamagata in Yamagata Prefecture. Work started in 1988, with Yamagata Shinkansen services commencing on 1 July 1992. Services were operated by a new fleet of 400 Series Shinkansen trains, at up to 240 km/h on the Tōhoku Shinkansen and 130 km/h on the Yamagata Shinkansen section. The success of this initiative led to the conversion of a further 61.5 km of the line to , opening on 4 December 1999.