History
Kōjimachi Station opened on 30 October 1974 as an underground stop on the Yūrakuchō Line of the Teito Rapid Transit Authority, in the Kōjimachi neighbourhood of Chiyoda, Tokyo. Its station number is Y-15. Operations passed to Tokyo Metro on 1 April 2004 when TRTA was privatised. The station's two side platforms are unusually stacked rather than side by side: platform 1 is on the second basement level (B2F) and platform 2 is one further down on the third basement level (B3F). The arrangement is dictated by the narrow tunnel alignment used in this part of central Tokyo.
History summarized from Japanese & English Wikipedia · last reviewed 2026-05-18.