The Yamanote Line is a loop service in Tokyo, Japan, operated by the East Japan Railway Company. 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.

The East Japan Railway Company is a major passenger railway company in Japan, the largest of the seven Japan Railways Group companies. The company name is officially abbreviated as JR-EAST or JR East in English, and as JR Higashi-Nihon in Japanese. The company's headquarters are in Yoyogi, Shibuya, Tokyo, next to Shinjuku Station. It is listed in the Tokyo Stock Exchange, is a constituent of the TOPIX Large70 index, and is one of three Japan Railways Group constituents of the Nikkei 225 index, the others being JR Central and JR West.