The is a subway line in Tokyo, Japan, operated by the municipal subway operator Toei Subway. The line runs between in à Âta and in Sumida. The line is named after the Asakusa district, a cultural center of Tokyo, under which it passes.
The Asakusa Line was the first subway line in Japan to offer through services with a private railway. Today, it has more through services to other lines than any other subway line in Tokyo. Keikyu operates through trains on the Keikyu Main Line to and the Keikyu Airport Line to . The Keisei Electric Railway operates through trains on the Keisei Oshiage Line to and the Keisei Main Line to , and the Shibayama Railway runs trains via the Keisei Main Line and the Shibayama Railway Line to . Via its through services with Keisei and Keikyu, the Asakusa line is the only train line that offers a direct connection between Tokyo's two main airports.
The Asakusa Line is often split into two routes: OshiageâÂÂSengakuji and SengakujiâÂÂNishi-magome; only some trains make all station stops on the line, as many trains travel on the Keikyu Main Line south of Sengakuji.
On maps and signboards, the line is shown in the color rose. Stations carry the letter "A" followed by a two-digit number inside a more reddish vermilion circle.
In fiscal year 2023, the Asakusa Line was Toei's most profitable line, earning 8.67 billion yen in surplus (a 26.4% profit margin). It served 683,003 passengers on average per day, the third highest in the Toei network.
The original plan for what is now the Asakusa Line was included in a report Tokyo City Notification No. 2 of 1920 () in 1920. The proposal outlined a route as Line 1 connecting âÂÂShinagawa Yatsuyama â Shimbashi â Tsukiji â Ryogoku West â Kaminarimon â OshiageâÂÂ.
A construction patent for this route was granted to the Tokyo Underground Light rail and Tokyo Railway (æ±京éÂÂéÂÂ). However, following the Great Kantà  Earthquake of 1923, the patent was revoked along with those for other planned lines because construction had not yet commenced.
On September 1, 1941, following the establishment of the Teito Rapid Transit Authority, all route licenses held by Tokyo City, the Tokyo Underground Railway, the Tokyo Rapid Railway, and the Keihin Underground Railway were transferred to the Teito Subway in exchange for a fee.
The routes for which licenses had been granted as of 1941 and which were later taken over for the construction of the Asakusa Line are as follows:
The line number is Line 1, because it was technically the first subway line in Tokyo to be planned in the 1920s as an underground route connecting the Keikyu and Keisei Electric Railway via , eventually allowing for through trains between these two railways. In its original plan form, the line would have actually bypassed Asakusa Station entirely. However, the plan was changed to take advantage of the existing Tobu Isesaki Line (section now named as the Tobu Skytree Line) and Tokyo Metro Ginza Line connections at Asakusa.
The Toei Asakusa Line was the first subway line constructed by the Tokyo Metropolitan Government.
Construction of this line began on 27 August 1956 after years of delays, and the initial segment between Oshiage and Asakusabashi opened on 4 December 1960. The line then opened in stages from north to south:
The line was named Asakusa Line on 1 July 1978.
From 1998 to 2002, the Asakusa Line was used as part of a rail connection between Tokyo's two major airports, Haneda and Narita. While a few trains still run between the airports, the service has greatly diminished in frequency since 2002.
In 2005, a research group of government, metropolitan and railway company officials proposed that the Asakusa Line be connected to Tokyo Station via a spur to the north of Takarachà  Station. This would provide Tokyo Station's first direct connection to the Toei subway network. It would also make it possible to reach Haneda Airport in 25 minutes (versus 35 minutes today) and Narita Airport in 40 minutes (versus 57 minutes today). This plan has yet to be finalized or formally adopted. Authorities are re-considering a similar plan as part of the infrastructure improvements for the 2020 Summer Olympics; the proposed line would cut travel time to Haneda from 30 minutes to 18 minutes, and to Narita from 55 minutes to 36 minutes, at a total cost of around 400 billion yen.
A variety of rolling stock is in use due to the large number of through service operators on the line, all of which use standard gauge tracks and 1,500 V DC electrification via overhead lines. Currently, six operators run trains onto the Asakusa Line, the most of any Tokyo subway line, and the line is unique as the only subway line in Tokyo with through services onto standard gauge railways (all other through services are with narrow gauge lines).