On This Day in 1979, Tokyo Metro Ayase to Kita‑Ayase Branch Opens

On this day in 1979, Tokyo’s subway network was expanded with the opening of a branch of the Chiyoda Line extending from Ayase to Kita‑Ayase. The Chiyoda Line had been constructed in stages since its first section opened in 1969, and by the late 1970s it had become an important north‑east to south‑west route through the city. The new branch, inaugurated on 20 December 1979, added a short spur to serve Tokyo’s Adachi ward and provide direct access to the line’s maintenance facilities.

The branch line runs approximately 2.1 kilometres north from Ayase Station to the newly built Kita‑Ayase Station, which opened on the same day. Kita‑Ayase became the sole passenger stop on the spur, bringing rail service to the local neighbourhood and connecting residents to the wider metro network via Ayase. The short extension also provided operational value by linking the main line with the adjacent rail depot used for storage and maintenance of Chiyoda Line trains.

At the time of its opening, passenger service on the branch was operated by a dedicated shuttle running between Ayase and Kita‑Ayase. This shuttle used three‑car trains, reflecting the relatively light demand on the new spur compared with the main line, which carried through services between far‑flung suburbs and central Tokyo. Passengers transferring between the branch and main line could do so at Ayase station, where they connected with Chiyoda Line trains bound for central destinations such as Otemachi and Yoyogi‑Uehara.

The inauguration of the Ayase–Kita‑Ayase branch on 20 December 1979 marked a modest but meaningful expansion of Tokyo’s subway system in response to the capital’s growing commuter needs. While short in length, the extension improved accessibility for local commuters and strengthened the operational capacity of the Chiyoda Line by linking it directly with the line’s depot. Over subsequent decades, this branch remained part of the Chiyoda Line infrastructure, later receiving upgrades to allow through services beyond Ayase as demand patterns evolved.