The Yamaguchi Line is a railway line in western Japan operated by West Japan Railway Company. The line connects Shin-Yamaguchi Station in Yamaguchi, Yamaguchi and Masuda Station in Masuda, Shimane.

The West Japan Railway Company, also referred to as JR West , is one of the Japan Railways Group companies and operates in western Honshu. It has its headquarters in Kita-ku, Osaka. It is listed in the Tokyo Stock Exchange, is a constituent of the TOPIX Large70 index, and is also one of only three Japan Railways Group constituents of the Nikkei 225 index: the others are JR East and JR Central. It was also listed in the Nagoya and Fukuoka stock exchanges until late 2020.