The E4 series (E4系) was a high-speed shinkansen train type operated by East Japan Railway Company in Japan. They were the second series of completely bi-level Shinkansen trainsets to be built in Japan. They previously operated on the Tōhoku and Jōetsu Shinkansen, and occasionally on the Nagano Shinkansen. E4 series trains feature double-decker cars to accommodate additional commuter traffic around Tokyo and other urban areas. They were often coupled to 400 series trains on the Tōhoku Shinkansen between Tokyo and Fukushima before the latter retired in April 2010 along with the E3 series trains until September 2012. The last trains of the E4 series were withdrawn from regular service on 1 October 2021.

The Shinkansen , colloquially known in English as the bullet train, is a network of high-speed railway lines in Japan. Initially, it was built to connect distant Japanese regions with Tokyo, the capital, to aid economic growth and development. Beyond long-distance travel, some sections around the largest metropolitan areas are used as a commuter rail network. It is owned by the Japan Railway Construction, Transport and Technology Agency and operated by five Japan Railways Group companies.