Around Shinjuku Station: before it was Shinjuku

Shinjuku Really Means a New Post Town

Shinjuku's name records a specific improvement to Edo's transportation network. Travelers on the Koshu Kaido highway faced a long journey from Nihonbashi to the first post station at Takaido. Local headman Takamatsu Kiroku and others petitioned for an additional stopping place. Permission was granted in 1698, and the new post town officially opened in 1699. Part of its site came from land returned to the shogunate by the Naito family, associated with the Takato Domain in present-day Nagano Prefecture. The settlement therefore became known as Naito Shinjuku, combining the family name with the words for a new lodging station. When Yotsuya, Ushigome, and Yodobashi wards merged on March 15, 1947, the already famous name Shinjuku was chosen for the new ward. Today's enormous transport hub retains the name of an Edo-period travel stop.

→ Explore Shinjuku Oiwake near Shinjuku-sanchome, where the Koshu and Ome highways once diverged.

Sources (in Japanese): 新宿区公式・新宿区について（名前の由来・歴史・地勢）, 新宿区公式・広報新宿 内藤新宿をたどる（2025年）, 新宿区公式・新宿区の紹介

Were Shinjuku's Skyscrapers Built Where Tokyo Once Filtered Its Drinking Water?

The land now occupied by the Tokyo Metropolitan Government Building and surrounding skyscrapers was once a vast water-treatment facility. Yodobashi Water Purification Plant began supplying water to the Kanda and Nihonbashi districts on December 1, 1898, marking the beginning of Tokyo's modern water-supply system. Water arriving through the Tamagawa Aqueduct was treated here before being distributed across the city.

A photograph taken around 1964 shows three sedimentation basins and 24 filtration basins stretching across the site. The plant closed on March 31, 1965, as urban development and plans for a new business district advanced.

Shinjuku Station itself opened in March 1885 on the Nippon Railway's Shinagawa Line. Surprisingly, its original location was not in the old Naito-Shinjuku district but in neighboring Tsunohazu village.

After the waterworks closed, the western station area was redeveloped into Shinjuku's skyscraper district. The current Tokyo Metropolitan Government complex was completed in 1991. Beneath one of Tokyo's most recognizable skylines lies the history of the infrastructure that supplied the growing capital with drinking water.

→ From the public spaces around the Tokyo Metropolitan Government Building, imagine the enormous water-treatment basins that once spread across this skyline.

Sources (in Japanese): 東京都水道局「東京近代水道ギャラリー」, 東京都水道歴史館「廃止直前の淀橋浄水場」, 東京都「未来に向けた新宿のまちづくり」, 財務省「路線価でひもとく街の歴史・新宿」