Shobojigawa Minamisawa Dam No. 6

Dam No. 6 carries an apron and revetment on its downstream face. The prefectural engineer who shaped the Shobojigawa survey, Kobata (木幡長命), is recorded in connection with these works.

This dam is one of a chain of erosion-control structures built along the Shobojigawa, a stream that runs through the Shimo-Oginoto district of Tendo City, Yamagata, and joins the Kuratsugawa on its way to the Mogami River. After a severe flood struck the valley in 1913, Yamagata Prefecture built a run of stone check dams and current-control works here between 1922 and 1927.

About fifty metres below No. 5. A stone apron and bank revetment on the downstream face help hold the ravine sides in place. The survey behind the Shobojigawa works was led by a prefectural engineer, Kobata (木幡長命).

Why It Matters

In all, the works comprise sixteen dams on the north branch, three on the Tanuki, and ten on the south, joined by gabion structures that steer the current. The idea was not one great wall but many modest ones in series, easing the gradient of a scoured torrent little by little.

The stonework is tanizumi, laid on the diagonal to spread the load, and nerizumi, mortared at the joints so the wall acts as one. Diagonal coursing of this kind resists water and earth pressure and suits a dam set in a fast mountain stream. Both faces are given a 3-bu batter, a nearly upright lean of about one in 3.3.

The dams were entered on the register of tangible cultural properties in 2005, valued as a record of early modern sabo engineering and as part of the fabric of the ravine landscape.

Seeing It Today

This is rough country on the edge of Tendo City, with no paved walkways. Visit only after checking the weather and the flow, and keep within safe bounds. Up close you can read the worked faces of the masonry, still holding water after a century, and the moss on the stone.

The dam measures 17 metres along its crest and stands 3.0 metres high. It belongs to the Minamisawa branch and was completed in 1926.

📍 Plan Your Visit to Yamagata
Find tours, activities & transport passes near Shohoji River Minamizawa No. 6 Stone Dam
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Q&A

QWhat exactly is a stone check dam?
AIt is a low masonry wall built across a mountain stream to trap gravel and sand and to slow the water, reducing the risk of debris flows downstream. These examples are made of dressed stone rather than concrete.
QCan I visit it, and is it free?
AThe dams stand on public land along the stream and can be seen from outside at no charge, but there are no visitor facilities, signs or guardrails. Treat it as backcountry and go prepared.
QWho surveyed and designed the works?
ARecords credit the survey of the Shobojigawa erosion-control works to a prefectural engineer, Kobata (木幡長命). Individual technicians oversaw construction at each site.
QWhen were these dams built and listed?
AThis one dates to 1926, part of works carried out between 1922 and 1927. The whole group was registered as a national tangible cultural property in 2005.

Basic Information

Name正法寺川南沢第六号石堰堤 (Shobojigawa Minamisawa Dam No. 6)
LocationShimo-Oginoto, Tendo City, Yamagata Prefecture
DesignationRegistered Tangible Cultural Property (structure), registered 2005; registration no. 06-0080
Date1926 (大正15年)
FormGravity-type stone check dam; crest length 17 m, height 3.0 m; 1 unit
OwnerYamagata Prefecture
AccessMountain stream; no visitor facilities. Open watercourse, viewable from public land.

References

National Database of Designated Cultural Properties, Agency for Cultural Affairs — 正法寺川南沢第六号石堰堤
https://kunishitei.bunka.go.jp/bsys/maindetails/101/00004889
Tendo City — Registered Tangible Cultural Properties
https://www.city.tendo.yamagata.jp/tourism/history/tourokubunkazaihoka.html
Cultural Heritage Online, National Institutes for Cultural Heritage — Yamagata / Tendo
https://bunka.nii.ac.jp/heritages/region/6/6210

Last verified: 2026.07.03