A Concrete Arch over the Tenryu River
The Sakato Bridge (坂戸橋) is a reinforced concrete arch bridge of 1932 in Okusa to Katagiri, Nakagawa Village, Kamiina District, Nagano Prefecture, and was designated an Important Cultural Property on December 23, 2020 (Agency for Cultural Affairs).
The Agency records a single-span reinforced concrete arch bridge, 77.9 metres long and 6.0 metres wide, with end posts and parapets, and with its wing walls, wing parapets and right-bank approach road included; designation number 2712.
A Parabolic Arch over the Tenryu
The Sakato Bridge carries a road over the upper Tenryu River at the gateway to the Southern Alps (Agency for Cultural Affairs). It was designed by the civil engineering section of Nagano Prefecture and built by the prefecture itself, to improve motor traffic in the mountains, and completed in 1932.
It is a large reinforced concrete arch bridge 78 metres long, its arch a parabola (Agency for Cultural Affairs). Joints between members are finished in smooth curves and the corners of the arch are chamfered, careful work down to the details. According to Nagano Prefecture, cherry trees and azaleas planted to celebrate the bridge grow nearby.
Why It Is an Important Cultural Property
The Agency notes that its 70-metre span is the largest surviving among Japanese road bridges built before the war, and values it as a measure of what road bridge engineering had achieved in the early Showa period.
What to Look For
Look for the 70-metre parabolic arch, the smoothly curved joints and the chamfered corners (Agency for Cultural Affairs). In spring the cherry trees planted for its opening frame the bridge (Nagano Prefecture).
Visiting
It is a road bridge owned by Nagano Prefecture (Agency for Cultural Affairs). According to the prefecture, it can be seen all year, with an information board, parking and a walking path on site, five minutes by car from the Nakagawa Village office.
Q&A
- When was the Sakato Bridge completed?
- In 1932 (Agency for Cultural Affairs).
- What kind of bridge is it?
- A reinforced concrete bridge 78 metres long with a parabolic arch.
- Why is it important?
- Its 70-metre span is the largest surviving on a prewar road bridge in Japan.
- Can I visit?
- Yes, all year, with parking and a walking path (Nagano Prefecture).
- When was the Sakato Bridge designated an Important Cultural Property?
- On December 23, 2020 (Agency for Cultural Affairs).
Basic Information
| Name | Sakato Bridge (坂戸橋) |
|---|---|
| Location | Okusa to Katagiri, Nakagawa Village, Kamiina District, Nagano Prefecture |
| Designation | Important Cultural Property (Structure) |
| Year Designated | Designated 2020/12/23 (Reiwa 2) |
| Quantity | 1 structure |
| Dimensions | Single-span reinforced concrete arch, 77.9 m long, 6.0 m wide |
| Owner | Nagano Prefecture |
| Public Access | 5 minutes by car from the Nakagawa Village office (Nagano Prefecture) |
References
- Sakato Bridge (Database of National Cultural Properties, Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/heritage/detail/102/00005278
- Sakato Bridge (Nagano Prefecture, Ina Construction Office)
- https://www.pref.nagano.lg.jp/inaken/jigyo/doga/documents/sakadobasi.pdf
Last verified: 2026.10.22