The entrance to Yotsuya-sanchome Station on Tokyo Metro’s Marunouchi Line (M11) is shown at night, featuring a clean, modern design with bright signage and red elevator doors. The station serves the Shinjuku district and connects to key destinations like Shinjuku, Ogikubo, and Tokyo Station. Braille paving and clear bilingual signs reflect Tokyo Metro’s accessibility standards and emphasis on wayfinding.

A passageway leading down to the Tokyo Metro Marunouchi Line, part of one of Tokyo’s oldest surviving subway corridors. The Marunouchi Line began opening in stages between 1954 and 1962, making it the second-oldest subway line in the city after the Ginza Line. Many stations along the route—especially the early central segments—retain architectural and material choices from Japan’s postwar reconstruction period, including ceramic wall tile, exposed conduit, and compact stairways built before modern accessibility standards were introduced.

The dense overhead wiring found in older Marunouchi Line interchanges reflects decades of retrofits to accommodate improved lighting, ventilation, fire-suppression systems, and communication networks, all integrated into the original structural envelope. These spaces remain essential transfer points connecting central Tokyo’s commercial districts with major JR East hubs such as Shinjuku, Tokyo Station, and Ochanomizu.

Although the Marunouchi Line has undergone rolling upgrades—including new rolling stock (02 series replacements), platform screen doors, and improved wayfinding—the underlying layout in many stations still conveys the functional, space-efficient design philosophy of mid-20th-century Japanese subway engineering.

Commuters wait for the next train on the Tokyo Metro Ginza Line, Japan’s oldest underground subway line and one of the city’s most heavily traveled routes. This platform—serving trains toward Toranomon, Akasaka-mitsuke, Omote-sando, and Shibuya—captures a typical weekday scene with riders lining up at designated doors, phones in hand, as screen doors stand ready to open with the arriving train.

Opened progressively between 1927 and 1939, the Ginza Line was Asia’s first subway, modeled after London’s Underground and New York’s early lines. Its development helped shape modern Tokyo by linking emerging commercial districts—including Asakusa, Ginza, and Shibuya—into a cohesive urban network. Today, despite being nearly a century old, the line remains a backbone of the city’s transportation system, continually upgraded with platform doors, advanced signaling, and refreshed stations to meet the demands of one of the world’s busiest transit cities.