A Flume under Granite Cliffs
The Watarase Keikoku Railway Yoshinosawa Flume (わたらせ渓谷鐵道吉ノ沢架樋) is a reinforced-concrete flume spanning the track built in 1935 at Sori, Azuma-cho, Midori City, Gunma Prefecture, and was registered as a Registered Tangible Cultural Property (structure) on November 2, 2009 (Agency for Cultural Affairs).
The Agency for Cultural Affairs records reinforced concrete, 14 metres long, with supports, registration number 10-0278.
The Ashio Copper Railway
According to Watarase Keikoku Railway, the Ashio copper mine, bought by Furukawa Ichibei in 1877, grew to produce half of Japan's copper, more than horses and a horse tramway could carry, so a railway was built from Kiryu to Ashio. The Ashio Railway opened to Omama in 1911, reached Ashio in December 1912 and was completed to Ashio Honzan in 1914. Nationalised in 1918 as the Ashio Line, it has been run by Watarase Keikoku Railway since 1989.
The Watarase Keikoku Railway Yoshinosawa Flume stands about 1,000 metres south-west of the Kasamatsu Tunnel (Agency for Cultural Affairs).
Value as a Registered Cultural Property
The Watarase Keikoku Railway Yoshinosawa Flume was registered as a structure contributing to the historic landscape of the country. The Agency for Cultural Affairs calls it a distinctive structure built across the track bed to keep rainwater and soil off the line.
What to Look For
The Agency for Cultural Affairs describes a steel frame of supports and girders made from old rails, carrying a reinforced-concrete trough 14 metres long and 2.7 metres wide.
Watarase Keikoku Railway's pamphlet explains that here the granite known as Sori mikage comes right down to the line, and the Watarase Keikoku Railway Yoshinosawa Flume was built to stop weathered granite washing onto the track.
Visiting
The Watarase Keikoku Railway Yoshinosawa Flume comes into view about four minutes after Sori Station on a Mato-bound train, or about three and a half minutes after Haramuko Station on a Kiryu-bound train (Watarase Keikoku Railway). Watarase Keikoku Railway notes that all of its registered structures can be seen from the train.
Do not enter the tracks; view it from the train, the station or nearby roads. It is located at Sori, Azuma-cho, Midori City, Gunma Prefecture. Of the line's 38 registered structures, the 26 in Gunma and 11 in Tochigi are gathered on the group pages Watarase Keikoku Railway (Gunma Section) and Watarase Keikoku Railway (Tochigi Section).
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Q&A
- When was it built?
- In 1935 (Agency for Cultural Affairs).
- How is it built?
- Reinforced concrete, 14 metres long, with supports (Agency for Cultural Affairs).
- What does it protect against?
- Weathered granite and rainwater washing onto the line (Watarase Keikoku Railway, Agency for Cultural Affairs).
- Where can it be seen?
- The Watarase Keikoku Railway Yoshinosawa Flume comes into view about four minutes after Sori Station on a Mato-bound train, or about three and a half minutes after Haramuko Station on a Kiryu-bound train (Watarase Keikoku Railway).
- When was the Watarase Keikoku Railway Yoshinosawa Flume registered?
- On November 2, 2009.
Basic Information
| Name | Watarase Keikoku Railway Yoshinosawa Flume (わたらせ渓谷鐵道吉ノ沢架樋) |
|---|---|
| Location | Sori, Azuma-cho, Midori City, Gunma Prefecture |
| Designation | Registered Tangible Cultural Property (Structure) |
| Year Designated | Registered 2009/11/02 (Heisei 21) |
| Quantity | 1 structure |
| Dimensions | Reinforced concrete, length 14 metres, with supports |
| Owner | Not listed in the national database (line operated by Watarase Keikoku Railway Co., Ltd.) |
| Public Access | Visible from the train |
References
- Watarase Keikoku Railway Yoshinosawa Flume (Database of National Cultural Properties, Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/heritage/detail/101/00007851
- Registered Tangible Cultural Properties (Watarase Keikoku Railway, in Japanese)
- https://www.watetsu.com/sightseeing/culture.php
- Pamphlet: Railway Heritage from the Train Window, map notes (Watarase Keikoku Railway, in Japanese)
- https://www.watetsu.com/assets/pdf/sightseeing/culture_yukei_des05.pdf
- History (Watarase Keikoku Railway, in Japanese)
- https://www.watetsu.com/company/history.php
Last verified: 2026.10.12
