What Is Bannai River No. 6 Sabo Dam?
Bannai River No. 6 Sabo Dam (万内川六号堰堤, Bannaigawa Rokugō Entei) is a stone-and-concrete sabo dam built around 1923 on the Bannai River in Nishinoya, Myoko City, Niigata Prefecture, and was registered as a Registered Tangible Cultural Property on March 18, 2003.
A sabo dam is a check dam that holds back sediment in a mountain stream. Bannai River No. 6 Sabo Dam is a gravity dam of stone and concrete, 37 meters long at the crest and 2.0 meters high, with revetments on both banks downstream and a secondary dam in front. It was remodeled around 1934, and its downstream face has a batter of 1:0.2.
Among the registered dams it lies above No. 4 and below the No. 7 and No. 8 dams, forming the bottom step of a stretch where three low dams cut the river into a staircase.
Why It Was Registered
The dam was registered as a structure contributing to the historic landscape of the country. What the Agency for Cultural Affairs dwells on is the spillway notch of Bannai River No. 6 Sabo Dam. The notch is cut down as deep as the dam is high, its shoulders slope at 1:1, and it runs 15 meters across.
The result, in the agency's words, is a clear line of sight upstream and a landscape in which low stone dams, settled into the terrain, follow one after another against the mountains. The dam is valued not only as a working sabo structure but for the way it shapes the view.
The prefecture's explorer map explains that sabo builders of the day had two approaches: a single tall, massive dam, or a series of low dams set in steps, as on the Bannai. It says the stepped series, an approach with European roots, was brought here as the most up-to-date technique in Japan at the time.
What to Look For
From Viewpoint 2, marked on the prefecture's explorer map, Bannai River No. 6 Sabo Dam and the No. 7 and No. 8 dams above it appear stacked like steps. At 2.0 meters, No. 6 sits in the foreground, its low line of stone drawing your eye up the valley to the dams beyond.
Look closely at the notch, the dip in the crest that gathers the water and lets it fall. Here it is cut wide, 15 meters across, and its shoulders run into the body of the dam at an easy slant. Stand in front and look upstream, and the view carries straight through the gap to the valley behind.
Fresh spring leaves and autumn color both set off the gray stone well. When snowmelt raises the flow, more water pours through the notch; that is the time to keep well back from the water's edge.
How to Visit
Bannai River No. 6 Sabo Dam lies upstream of No. 4. For the fullest view, look at it together with No. 7 and No. 8 from Viewpoint 2 on the prefecture's explorer map.
Bannai River No. 6 Sabo Dam stands in the open and can be viewed freely from the path; neither the prefecture nor the city lists any restriction on photography. It is a working sabo structure, so stay off the crest and the spillway notch, and keep back from the water after heavy rain. Opening season and directions to Bannai River Sabo Park are covered on the Bannai River Sabo Facilities page.
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- Find tours, activities & transport passes near Bannai River No. 6 Sabo Dam
- [ Sado Island & Echigo-Yuzawa Ski Resort Tours ]
Q&A
- When was Bannai River No. 6 Sabo Dam built?
- Around 1923, with a remodeling around 1934. It belongs to the sabo project Niigata Prefecture began on the Bannai River in 1921.
- Why is Bannai River No. 6 Sabo Dam a Registered Tangible Cultural Property?
- It was registered on March 18, 2003, as a structure contributing to the historic landscape. Its deeply cut, 15-meter notch keeps the view upstream open and lets the low stone dams read as a series against the mountains.
- Where is the best place to see Bannai River No. 6 Sabo Dam?
- Viewpoint 2 on the prefecture's explorer map, where No. 6 and the No. 7 and No. 8 dams upstream can be seen together as a staircase.
- Can I visit Bannai River No. 6 Sabo Dam, and is there a fee?
- Yes. It is outdoors and can be seen freely from the path. Bannai River Sabo Park is open from April to November and there is no charge.
- Where is Bannai River No. 6 Sabo Dam?
- Bannai River No. Directions to Bannai River Sabo Park are on the Bannai River Sabo Facilities page.
Basic Information
| Name | Bannai River No. 6 Sabo Dam (万内川六号堰堤) |
|---|---|
| Location | Nishinoya, Myoko City, Niigata Prefecture |
| Designation | Registered Tangible Cultural Property (Structure), Registration No. 15-0148 |
| Year Designated | Registered 2003/3/18 (Heisei 15) |
| Quantity | 1 structure |
| Dimensions | Crest length 37 meters, height 2.0 meters |
| Owner | Niigata Prefecture |
| Public Access | Outdoors and freely viewable; Bannai River Sabo Park is open April to November, free of charge |
References
- Agency for Cultural Affairs, Database of National Cultural Properties: 万内川六号堰堤
- https://kunishitei.bunka.go.jp/bsys/maindetails/101/00003215
- Niigata Prefecture: Bannai River stone sabo dams (Registered Tangible Cultural Properties)
- https://www.pref.niigata.lg.jp/sec/jouetsu_sabou/bunkazai-bannai.html
- Niigata Prefecture: Explorer map of registered dams No. 1 to No. 4 (PDF)
- https://www.pref.niigata.lg.jp/uploaded/attachment/48362.pdf
- JSCE Kanto Branch: Bannai River sabo dams and Hikagesawa ground sills
- https://www.jsce.or.jp/branch/kanto/04_isan/h29/h29_8.html
Last verified: 2026.09.24
