In 1920,
Tokyo City, the administrative predecessor of today’s
23 special wards, announced its first formal subway development proposal through
Tokyo City Notification No. 2 of 1920 (), designating seven routes. Consistent with the city’s broader policy of public ownership and operation of urban transportation, the network was intended to be constructed and managed municipally. However, the
Great Kantō Earthquake struck on September 1, 1923, inflicting catastrophic damage on central Tokyo and altering the city’s urban and transportation planning priorities. In 1925, the
Ministry of Home Affairs issued
Ministry of Home Affairs Notification No. 56 of 1925 (), which formally designated five routes. Under this framework, Tokyo City obtained operating licenses for four of the five proposed subway lines. However, burdened by substantial
public debt in the aftermath of earthquake reconstruction, the city faced strong opposition from both the Ministry of Home Affairs and the
Ministry of Finance. As a result, Tokyo City was unable to secure final approval to commence construction, effectively halting its municipal subway plans. After the outbreak of
World War II, the Japanese government integrated these two companies in 1941 to form the
Teito Rapid Transit Authority (TRTA), commonly known as
Eidan, which later became the predecessor of today's
Tokyo Metro.
Postwar construction In Tokyo during the 1950s,
post–World War II economic expansion led to rapid population growth and a sharp increase in road traffic. As a result, the effectiveness of existing public transport infrastructure, such as the
Tokyo Toden (tram) system, steadily declined due to chronic road congestion, while the existing
Teito Rapid Transit Authority subway network alone was unable to keep pace with rising transportation demand. In 1954, the
Tokyo Metropolitan Assembly adopted a resolution to construct a public subway system in addition to the network operated by the Teito Rapid Transit Authority. In accordance with urban planning directives, the Tokyo Metropolitan government Tokyo Metropolitan Bureau of Transportation and
Keikyu corporation obtained a license from the Teito Rapid Transit Authority to build its first line between
Kuramae and
Magome, and began construction of the line as part of the Toei Subway system in 1958. Since the Toei Subway began operations on the Asakusa Line between
Asakusabashi and
Oshiage in 1960, with through services to the
Keisei Line, the system has expanded steadily, with the opening of the
Mita Line in December 1968, the
Shinjuku Line in December 1978, and the
Ōedo Line in December 1991. The Mita Line was extended between
Meguro and Mita stations, and the Ōedo Line entered full operation. == Lines ==