The Symmetrical Second Dam
The Ashizawa No. 2 Stone Masonry Dam (芦澤第二号石積堰堤, Ashizawa dai-nigō ishizumi entei) is a dry-laid stone sabo dam built in 1887 across the Ashizawa stream in Asa, Omi Village, Higashichikuma District, Nagano Prefecture, and it was entered on the national register as a Registered Tangible Cultural Property on October 7, 2014. Its registration number is 20-0456, and it belongs to Nagano Prefecture.
It is the second of the four Meiji-era stone dams counting from the bottom of the valley, standing 90 metres upstream of No. 1. No. 3 lies a further 190 metres beyond.
The Ashizawa No. 2 Stone Masonry Dam is 12 metres long at the crest and 3.8 metres high, the lowest of the four. Nagano Prefecture's Saigawa Sabo Office gives the crest length as 12.3 metres. The Agency for Cultural Affairs describes it as built almost perfectly symmetrical.
Why It Was Registered
The dam was registered for contributing to the historic landscape of the country, and the Agency's note on it is all about shape. Its nearly symmetrical body separates a central spillway notch from the wing sections on either side with straight, clearly defined lines, a modern elevation that the Agency says it shares with the other three dams.
The material is rough, the outline is not. The geometry suggests that by 1887 the Home Ministry's engineers were treating the profile of a sabo dam as something to be designed rather than simply piled up.
The stones are undressed andesite and other fieldstones about 50 to 120 centimetres across, laid without mortar in the mutsumaki dry-stone technique. According to the Saigawa Sabo Office, Ashizawa No. 2 and its three companions still function as sabo structures.
What to Look For
Try to take in the Ashizawa No. 2 Stone Masonry Dam from straight in front. The symmetry the Agency describes is easy to see from there, with the wings rising in balance on either side of the central spillway.
At 3.8 metres, the crest sits close to eye level, which makes this the easiest of the four on which to read the crisp step between spillway and wings.
Compare it with its neighbours: No. 1 below is 4.2 metres high and No. 3 above stretches 16 metres. Built in the same year under the same project, each dam was given its own length and height, and No. 2 is the most compact of the set.
Visiting No. 2
The Ashizawa No. 2 Stone Masonry Dam is an open-air structure with no fee and no booking. Walking up the streamside path, it appears about 90 metres past No. 1. Nagano Prefecture lists no visiting conditions and recommends spring through autumn.
View it from the path rather than climbing onto the face or into the spillway. The prefectural materials state no restrictions on photography. Directions to the valley, parking and the layout of the full walk are covered on the Ashizawa Stone Masonry Dams page.
- 📍 Plan Your Visit to Nagano
- Find tours, activities & transport passes near Ashizawa No. 2 Stone Masonry Dam
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Q&A
- When was the Ashizawa No. 2 Stone Masonry Dam built and registered?
- It was built in 1887 and registered as a Registered Tangible Cultural Property on October 7, 2014, under registration number 20-0456.
- How big is the Ashizawa No. 2 Stone Masonry Dam?
- The Agency for Cultural Affairs records it as 12 metres long and 3.8 metres high, the lowest of the four. The Saigawa Sabo Office gives the crest length as 12.3 metres.
- What is distinctive about the Ashizawa No. 2 Stone Masonry Dam?
- It is almost symmetrical, with a central spillway clearly divided from the wings by straight lines, which the Agency for Cultural Affairs describes as a modern elevation.
- Where can I see the Ashizawa No. 2 Stone Masonry Dam from?
- From the streamside path, 90 metres upstream of No. 1. There is no fee or booking. For safety, do not climb onto the dam.
- Does the Ashizawa No. 2 Stone Masonry Dam still work as a sabo dam?
- Yes. According to the Saigawa Sabo Office, No. 2 and the other three Ashizawa dams still function as sabo structures.
Basic Information
| Name | Ashizawa No. 2 Stone Masonry Dam (芦澤第二号石積堰堤) |
|---|---|
| Location | Aza Ashizawa, Asa, Omi Village, Higashichikuma District, Nagano Prefecture |
| Designation | Registered Tangible Cultural Property (Structure) |
| Year Designated | Registered 2014/10/7 (Heisei 26), registration no. 20-0456 |
| Quantity | 1 structure |
| Dimensions | Crest length 12 metres, height 3.8 metres |
| Owner | Nagano Prefecture |
| Public Access | Open-air sabo structure; free access; recommended season spring to autumn (Nagano Prefecture sabo division) |
References
- Ashizawa No. 2 Stone Masonry Dam (Database of National Cultural Properties, Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/bsys/maindetails/101/00010146
- Ashizawa No. 2 Stone Masonry Dam (Cultural Heritage Online)
- https://online.bunka.go.jp/heritages/detail/287989
- Ashizawa No. 1 Stone Masonry Dam (Database of National Cultural Properties, Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/bsys/maindetails/101/00010145
- Ashizawa No. 3 Stone Masonry Dam (Database of National Cultural Properties, Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/bsys/maindetails/101/00010147
- Ashizawa stone masonry dams, Omi Village (Nagano Prefecture Saigawa Sabo Office)
- https://www.pref.nagano.lg.jp/saisabo/jigyo/ashizawa201403.html
Last verified: 2026.10.06
