Shohoji River Tanukizawa No. 2 Stone Dam

Shobojigawa Tanukisawa Dam No. 2

Set where the ravine pinches to its narrowest, Dam No. 2 is the shortest in the series at 6.4 metres. Here the terrain dictated the shape of the wall.

The Shobojigawa flows out of the hills at Shimo-Oginoto in Tendo City and feeds, by way of the Kuratsugawa, into the Mogami River system. A major flood in 1913 set the prefecture to work: from 1922 to 1927 it laid down a sequence of stone dams along the ravine, and this is one of them.

About thirty metres below Dam No. 1, it sits in a narrow gorge cut by vertical erosion, its body shaped to the ground it occupies. A square drainage hole opens at the lower centre.

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. The downstream face carries a 3-bu batter.

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 6.4 metres along its crest and stands 2.6 metres high. It belongs to the Tanukisawa branch and was completed in 1923.