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Tokyo Walking Guide · History & Literature

The Tamagawa Josui Aqueduct:
The Canal That Built Edo Tokyo in 1653

Walk Its Green Promenade, Visit Dazai Osamu’s Grave & Finish at Inokashira Park

🏛️ Edo engineering masterpiece (1653)

✍️ Dazai Osamu literary walk

🌸 Cherry blossom tunnel (spring)

🌳 Inokashira Park finale

The Canal That Made Tokyo Possible

Most Tokyo residents walk past it without registering it. But the narrow green corridor that runs through the western suburbs of the city — the Tamagawa Josui greenway — was once the artery that kept Edo alive.

In 1653, the Tokugawa shogunate commissioned two private citizens — brothers Tama-gawa Shoemon and Seiemon — to build a water supply system for Edo, whose population was exploding beyond the capacity of existing wells. Their task: channel water from the Tamagawa River in Hamura, 43 kilometers west, to the Yotsuya district of central Edo — maintaining a precise gradient throughout, without modern surveying equipment, in 8 months.

They succeeded. The resulting Tamagawa Josui aqueduct served as Edo’s primary water source for roughly 250 years, with an average slope of just 2.1 meters per kilometer across its full 43km length. That precision, achieved without modern instruments, remains remarkable to civil engineers today.

The canal was decommissioned for water supply in 1898 when modern filtration facilities opened. What remains is a 43km green trail through western Tokyo — and a story most visitors never hear.

Key Facts

Dazai Osamu & the Literary Walk

The modern recognition of the Tamagawa Josui greenway is inseparable from one name: Dazai Osamu (1909–1948).

Japan’s most internationally read modern novelist — author of No Longer Human, The Setting Sun, and Run, Melos! — spent his final years in Mitaka, walking the Tamagawa Josui promenade. In June 1948, at age 38, Dazai died in the canal’s waters. His work remains central to literary culture across East Asia, and travelers from China, South Korea, and Taiwan make specific visits to Mitaka in his memory.

Every June 19th — simultaneously his birthday and the date his body was discovered — the Outo-ki memorial gathering brings Dazai readers from across Japan to Mitaka’s Zenrinji Temple, where he is buried.

Dazai Literary Walk Sites

Dazai Osamu Literary Salon (Mitaka City) — Near Mitaka Station’s south exit. Free exhibits covering Dazai’s years in Mitaka: manuscripts, personal effects, photographs. Essential stop for readers.

Zenrinji Temple (Mitaka) — Dazai’s grave, shared grounds with novelist Mori Ogai. Two foundational figures of Japanese modern literature buried in the same small temple — extraordinary for literary visitors. 15 min walk from Mitaka Station.

Recommended Walking Route: Mitaka to Kichijoji (~5km)

Difficulty: ★☆☆☆☆ · Flat throughout · 1.5–2 hours

Mitaka Station
↓ 10 min walk
Dazai Osamu Literary Salon
↓ 15 min walk
Zenrinji Temple (Dazai’s grave)
↓ 5 min walk
Tamagawa Josui Greenway (enter here)
↓ 60 min walk along the promenade
Inokashira Park
↓ 10 min walk
Kichijoji Station (end)

✦ Spring (late March–early April): Cherry trees line both sides of the greenway for much of this route, forming a nearly continuous tunnel of blossom. The walk is exceptional in any season but extraordinary in spring.

Inokashira Park — The Perfect Ending

Opened in 1917, Inokashira Park centers on a spring-fed pond (Inokashira-ike) fed by the same watershed that historically supplied the Tamagawa Josui. Rowboats are available for hire on the pond. The surrounding forest is one of the quietest large green spaces in the western Tokyo suburbs. The park’s atmosphere — families, students, musicians, people simply sitting — captures the Kichijoji neighborhood’s famous quality of life in concentrated form.

Ending the Tamagawa Josui walk here, having connected Edo engineering history with literary memory and arrived at a beloved park, creates one of the more satisfying day-walk structures available anywhere in Tokyo.

The Source: Hamura Intake Weir

For travelers who want to follow the aqueduct from its origin: the Hamura Intake Weir (Hamura Shusuizeki) in Hamura City is where the Tamagawa Josui began. The original intake structure, still drawing water from the Tamagawa River for Tokyo’s water supply today, is accessible from Hamura Station on the JR Ome Line. The grounds are open to visitors, and the scale of the weir — modest, precise, engineered for centuries — is quietly impressive.

The riverbanks around Hamura are a cherry blossom destination in spring (approximately 1,500 trees), and the Hamura Cherry Blossom Festival takes place annually in late March–early April.

Access Summary

Who Should Walk the Tamagawa Josui?

✔ Dazai Osamu readers & Japanese literature fans

✔ History & Edo-period culture seekers

✔ Cherry blossom season walkers

✔ Kichijoji / Mitaka area explorers

✔ Travelers who want Tokyo’s quiet side