The is a subway line in Tokyo, Japan, owned and operated by Tokyo Metro.
The line is named after the west gate of the Tokyo Imperial Palace, Hanzà Âmon (), which in turn is named after 16th century samurai Hattori Hanzà Â, who was important to the founding of the shogunate which built the palace. The Hanzà Âmon Line's color on maps and station guides is purple, and stations carry the letter "Z" followed by a two-digit number.
The line serves the wards of Shibuya, Minato, Chiyoda, Chà «à Â, Kà Âtà Â, and Sumida. Despite being shorter in length than nearly all other Tokyo subway lines, the Hanzà Âmon Line operates some of the longest through services with private railways â namely Tà Âkyà « Corporation and Tobu Railway. The line is connected to Tà Âkyà « Den-en-toshi Line at Shibuya Station to the south, and to the Tobu Skytree Line at to the north. Through trains operate between on the Tà Âkyà « Den-en-toshi Line and on the Tobu Skytree Line, onward to on the Tobu Isesaki Line and on the Tobu Nikko Line. Through-service trains between Chà «à Â-Rinkan and Minami-Kurihashi cover a total distance of in a single run â nearly six times the length of the Hanzà Âmon Line alone.
The Hanzà Âmon Line has direct interchanges with all other Tokyo Metro and Toei lines. It connects with the Tokyo Metro Ginza Line at five stations (the four stations between Shibuya and Nagatachà Â, as well as at Mitsukoshimae Station.
According to the Tokyo Metropolitan Bureau of Transportation, as of June 2009 the Hanzà Âmon Line is the sixth most crowded subway line in Tokyo, at its peak running at 173% capacity between Shibuya and Omotesandà  stations.
The Hanzà Âmon Line was first planned in 1968, along with the Chiyoda Line and Yà «rakuchà  Line, as a reliever line for the heavily congested Ginza Line. Its initial routing was from Futako-Tamagawa Station on the Tà Âkyà « Den-en-toshi Line to a new station in the Fukagawa district of Kà Âtà Â. In 1985, a second draft plan from the Ministry of Transportation moved the Hanzà Âmon Line's final terminus to Matsudo. During the planning stage, it was known as Line 11.
Construction began in 1972 and the majority of the line was expected to open in 1975. However, the Teito Rapid Transit Authority did not have enough funds to build the line, which delayed its construction. On August 1, 1978, the first section of the Hanzà Âmon Line finally opened from Shibuya to Aoyama-itchà Âme, including through services with the Den-en-toshi Line. It was then extended to Nagatachà  Station in September 1979. The line was initially operated mainly using Tokyu rolling stock, as the first TRTA 8000 series train did not enter service until 1981.
However, the next extension posed political problems, as the original plan had the line run directly under the Imperial Palace to à Âtemachi Station. TRTA decided to divert the route around the north side of the Imperial Palace, which required the construction of three new stations. An eminent domain battle erupted with landowners along the proposed route, which delayed the completion of the next stage of the line. Hanzà Âmon Station opened in December 1982, and the full extension around the Imperial Palace, terminating at Mitsukoshi-mae, was not completed until January 1989. The line was then extended to Suitengu-mae in November 1990 and finally Oshiage in March 2003, the latter also enabling through service with the Tobu Skytree Line.
The line, station facilities, rolling stock, and related assets were inherited by Tokyo Metro after the privatization of the Teito Rapid Transit Authority (TRTA) in 2004.
The Ministry of Transportation recommended in 2000 that the line be extended to its intended terminus in Matsudo by 2015. However, Tokyo Metro stated in its initial public offering that its construction operations would cease once the Fukutoshin Line is completed, which cast some doubt as to whether the Matsudo extension will actually be built.
All Hanzà Âmon Line rolling stock owned by Tokyo Metro are stored and maintained at Saginuma Depot <small>()</small>, located near Saginuma Station on the Tokyu Den-en-toshi Line.
a. Crowding levels defined by the Ministry of Land, Infrastructure, Transport and Tourism: