御堂筋線
The is a rapid transit line in Osaka, Japan, operated by Osaka Metro. Constructed under Midōsuji, a major north-south street, it is the oldest line in the Osaka subway system and the second oldest in Japan, following the Tokyo Metro Ginza Line. Its official name is , while the Osaka Municipal Transportation Bureau refers to it as , and in MLIT publications it is referred to as . On line maps, stations on the Midōsuji Line are indicated with the letter "M".