The Tokyo Metro Fukutoshin Line (東京メトロ副都心線, Tōkyō Metoro Fukutoshin-sen), formally the No. 13 Fukutoshin Line (13号線副都心線, Jūsangō-sen Fukutoshin-sen), is a 20.2-kilometer (12.6 mi) subway line operated by Tokyo Metro in west-central Tokyo and Wako, Saitama, Japan. The newest line in the Tokyo subway network, it opened in stages between 1994 and 2008. On average, the Fukutoshin Line carried 362,654 passengers daily in 2017, the lowest of all Tokyo Metro lines and roughly one third of its sister Tokyo Metro Yūrakuchō Line (1,124,478).