History
Hongō-sanchōme Station opened on 20 January 1954 as a Teito Rapid Transit Authority Marunouchi Line stop. The original side platforms were 80 m long, sized for four-car trains, with 40 m of tunnel reserved at the Ikebukuro end for future expansion; that extension was carried out in 1960 to allow six-car operation. The April 1965 residential-address reform shifted the surrounding district from Hongō 3-chōme to Hongō 2-chōme without moving the station. Toei opened a separate Ōedo Line platform here on 12 December 2000; the two stations are not connected underground because building a through-passage would have required acquiring private land. A two-year rebuild of the Marunouchi entrance finished on 22 November 2002, and platform doors entered service in 2006.
History summarized from Japanese & English Wikipedia · last reviewed 2026-05-18.
Notes
Because Tokyo Metro and Toei chose not to fund a connecting under-street passage to keep land-acquisition costs down, transferring between the Marunouchi and Ōedo lines at Hongō-sanchōme requires leaving the paid area and crossing two streets; Tokyo Metro reconsidered the linkage in 2011 but no through-passage has been built.