A Square Opening in the Stone

A square opening about a metre across pierces the base of Shimizugawa Dam No. 1, low and central beneath the spillway. It is the kind of detail that rewards a second look: on a masonry check dam, so large a weep hole is unusual, and it hints at how carefully the builders thought about letting ordinary flow pass while holding back the gravel and driftwood of a flood. Completed in 1937 (Showa 12), the dam crosses the upper Shimizu River in the Sekigane district of Kurayoshi, Tottori Prefecture, in the forested hills of western Japan.

No. 1 is the earliest of five erosion-control dams that the national government built along this short mountain river, and at 7.0 metres it is also the tallest. It sits roughly one kilometre downstream of Dam No. 5, the uppermost of the group.

Born of a Disaster

The trigger was a storm. In September 1934 the Muroto Typhoon tore across western Japan and swelled the rivers of the Tenjin system, of which the Shimizu is a tributary. In the years that followed, the Home Ministry, the arm of central government then responsible for public works, laid out a chain of sabo (erosion-control) dams to trap sediment and steady the torrent before it reached the farmland downstream. Work on the Shimizu group ran from 1937 to 1944, and No. 1 was the first to be finished.

The dam is a concrete gravity structure faced in mortared stone, a technique called neri-zumi. Most of its face is laid in tani-zumi, a diagonal coursing in which the blocks meet point to point, while the top layer of the spillway crest switches to nuno-zumi, level horizontal masonry. That pairing recurs across the Shimizu dams and gives them a shared handwriting. In 2004 the five surviving dams were listed as Registered Tangible Cultural Properties for their contribution to the historic landscape of the region.

Reading the Wall

Stand below the dam and the weep hole reads almost like an eye set in the stonework; above it the crest steps up in a single band of coursed blocks that catches the light differently from the diagonal work around it. In summer the surrounding slopes are dense green, the result of a century of replanting on hillsides that erosion had once stripped bare. The masonry has weathered to a soft grey that settles into the woods rather than standing apart from them.

These are working structures on public land, out in the open air along the river, so there is no gate and no admission. They lie in mountain country, though, reached by narrow forest roads, and the former spa town of Sekigane and the uplands toward Mt. Hiruzen make a natural base for a visit. Footing near the water can be uneven, and anyone planning to walk in close should check conditions locally first.

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Q&A

QWhen was Shimizugawa Dam No. 1 built?
AIt was completed in 1937 (Showa 12), making it the earliest of the five registered Shimizu River dams.
QWhat makes No. 1 stand out from the others?
AAt 7.0 metres it is the tallest of the group, and its spillway has an unusually large weep hole, roughly a metre square, at the centre of its base.
QWhy were these dams built here?
AThey are sabo (erosion-control) dams, built by the national government after the 1934 Muroto Typhoon to hold back flood sediment on the upper Tenjin River system.
QWhat does tani-zumi mean?
AIt is a masonry pattern in which stones are set diagonally, meeting point to point. Most of the dam's face uses it, with level nuno-zumi coursing along the spillway crest.
QCan visitors go and see the dam?
AYes. It is an outdoor civil structure on public land with no admission, though it lies in remote forest country best reached by car.

Basic Information

NameShimizugawa Dam No. 1 (清水川第一堰堤)
LocationHori, Sekigane-cho, Kurayoshi City, Tottori Prefecture
DesignationRegistered Tangible Cultural Property (structure); registered 23 July 2004
Registration No.31-0065
Completed1937 (Showa 12)
StructureConcrete gravity dam faced in mortared stone; length 52 m, height 7.0 m
Quantity1 structure
OwnerThe State (Ministry of Land, Infrastructure, Transport and Tourism)
AccessOutdoor structure on public land; no admission; remote, reached by car

References

Agency for Cultural Affairs, National Cultural Properties Database — Shimizugawa Dam No. 1
https://kunishitei.bunka.go.jp/bsys/maindetails/101/00004292
Cultural Heritage Online — Cultural Properties of Kurayoshi City, Tottori
https://bunka.nii.ac.jp/heritages/region/31/31203
MLIT, River Data Book — Tenjin River System
https://www.mlit.go.jp/river/toukei_chousa/kasen/jiten/nihon_kawa/0711_tenjin/0711_tenjin_01.html
MLIT — Sabo (Erosion and Sediment Control)
https://www.mlit.go.jp/river/sabo/index.html

Last verified: 2026.07.05