The E257 series (E257系, E257-kei) is a DC electric multiple unit (EMU) train type operated in Japan for limited express services by East Japan Railway Company (JR East) and built jointly by Hitachi, Kinki Sharyo, and Tokyu Car Corporation.

[citation needed] This sub-series was introduced on 1 December 2001 to replace the aging 183 and 189 series rolling stock on Chuo Main Line Azusa and Kaiji services.

[2] From the start of the revised timetable on 16 March 2019, E257 series trains were no longer used on regular Chuo Main Line limited express services.

The trains were modified into E257-2000 series trainsets and redeployed on Tokaido Main Line Odoriko services from 14 March 2020.

[4] The E257-500 sub-series version was delivered between July 2004 and October 2005, with the first sets entering service from 16 October 2004 on Uchibo Line Sazanami and Sotobo Line Wakashio limited-express services, replacing older 183 series rolling stock.

[11][better source needed] In December 2022, JR East announced that E257-5500 series sets would be used on Kusatsu Shima and Akagi limited express services on the Takasaki Line.

[12][13] They made their first trips on these services at the start of JR East's 18 March 2023 timetable revision, replacing 651-1000 series 7-car sets.