The Midosuji Line (御堂筋線) is the oldest and most traveled line of the Osaka Municipal Subway system. The Umeda-Shinsaibashi portion opened in 1933, and the line was gradually expanded over the next few decades, reaching its current length in 1987.
The Senri-Esaka portion is operated by the Kita-Osaka Kyuko Railway, but is seamless with the rest of the line.