History
Kōrakuen Station's Marunouchi Line platforms opened on 20 January 1954 on the Teito Rapid Transit Authority's second subway line. A two-track stabling siding entered use on 5 August 1958 to absorb fleet growth from the Marunouchi Shinjuku extension. On 15 April 1994 the Metro M Kōrakuen building opened, the first commercial development built directly over a TRTA station. The Namboku Line platforms — built 37.5 m underground to thread between Tokyo Dome and adjacent building foundations — opened on 26 March 1996, making the station a transfer between the two lines. Tokyo Metro succeeded the TRTA on 1 April 2004, and a "Take Me Out to the Ball Game" Namboku-platform jingle was introduced on 13 March 2015.
History summarized from Japanese & English Wikipedia · last reviewed 2026-05-18.
Notes
The Marunouchi Line platforms sit 3.5 m above ground and the Namboku Line island platform is 37.5 m below it, giving Kōrakuen a vertical difference of about 41 m between platforms — the greatest of any single subway station in Tokyo.