 The pre-series train was formally shown off to the media on 2 August 2015.

, the train was still undergoing test running.In October 2017, JR East announced that the first trains would enter revenue service on "Super Azusa" services from 23 December 2017, by which date three pairs of (9+3-car) trainsets would be available.The trains were awarded the 2018 Laurel Prize by the Japan Railfan Club.