The Yamanote Line (Japanese: 山手線, romanized: Yamanote-sen) is a railway loop service in Tokyo, Japan, operated by the East Japan Railway Company (JR East). It is one of Tokyo's busiest and most important lines, connecting most of Tokyo's major stations and urban centres, including Marunouchi, the Yūrakuchō/Ginza area, Shinagawa, Shibuya, Shinjuku, Ikebukuro, and Ueno, with all but two of its 30 stations connecting to other railway or underground (subway) lines.
Internally, JR East refers to the "Yamanote Line" as the quadruple-track 20.6-kilometre (12.8 mi) corridor between Shinagawa and Tabata via Shinjuku. The corridor consists of a pair of tracks used by Yamanote local trains and another parallel pair of tracks called "the Yamanote Freight Line" used by the Saikyō and Shōnan-Shinjuku line trains, some limited express services, and freight trains. In everyday usage, branding on maps and station signage, the "Yamanote Line" refers to the local service (also called "system") running the entire 34.5 km (21.4 mi) line looping between the Yamanote corridor via Shinjuku Station and the central portions of the Tōhoku and Tōkaidō Main Lines Via Tokyo Station. (This article uses the same definition unless noted otherwise.)