Japan’s Eidan Subway Chiyoda Line Opens First Segment

On December 15, 1967, the Teito Rapid Transit Authority (Eidan, later Tokyo Metro) opened the initial segment of the Chiyoda Line between Kita‑Senju and Ōtemachi. The Chiyoda Line was planned as a major north–south axis intended to relieve severe congestion on existing Tokyo subway routes. The first section connected the rapidly expanding suburbs of northeastern Tokyo with the city’s central business district, allowing more efficient commuter flows into Ōtemachi, one of Japan’s most important office hubs. The Chiyoda Line would later expand southwest toward Yoyogi‑Uehara, including through‑service connections with Japanese National Railways (JNR) and Odakyu Electric Railway, pioneering integrated metropolitan rail operations. The 1967 opening established operational strategies still seen today in Tokyo’s transit network, including bidirectional peak scheduling, cross‑platform transfers, and coordinated timetable planning with suburban private railways. The Chiyoda Line remains one of Tokyo Metro’s most heavily used corridors, and its initial launch represented a key step in the modernization of urban passenger rail in post‑war Japan.