A Tokyo Metro Marunouchi Line train approaches its terminal platforms during a March 2023 visit. The Marunouchi Line, one of Tokyo’s earliest postwar subway routes, opened in 1954 and played a key role in connecting the expanding Yamanote district centers with government and commercial areas in central Tokyo. Its distinctive red livery has remained a defining visual identity for decades, even as the rolling stock has undergone multiple modernizations.

Ikebukuro, the northern terminus of the line, is one of Tokyo’s busiest rail hubs, jointly served by JR East, the Seibu and Tobu railway networks, and several Metro lines. The station complex was heavily rebuilt throughout the late 20th century to handle increasing commuter volumes, resulting in the multi-level platform and passageway layout still in use today.

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.