The Longest Stone Span of Its Day
The Kokan Bridge (虹澗橋) is a single-arch stone bridge of 1824 in Notsumachi Nishihata, Usuki City, and Miemachi Sugo, Bungo-Ono City, Oita Prefecture, and was designated an Important Cultural Property on December 1, 1999 (Agency for Cultural Affairs).
The Agency records a single-arch stone bridge with parapets, designated together with a stone monument; designation number 02376.
Built by Three Merchants
The Kokan Bridge is a single-arch stone bridge over the Mie River, part of the Ono River system, on the boundary between the former towns of Nozu and Mie in southern Oita (Agency for Cultural Affairs). Three wealthy local merchants resolved to build it; designed by a stonemason, it was begun in January 1821 and finished in June 1824.
It is 31.0 metres long and 6.1 metres wide, and its nearly semicircular arch spans 25.1 metres (Agency for Cultural Affairs). It rests on the bedrock of the gorge, and its body and parapets are of Aso welded tuff, easy to quarry in the Ono River basin.
Why It Is an Important Cultural Property
The Agency notes that it had the longest span of any stone bridge in Japan when built, breaking through the limits of the small stone bridges of Kyushu until then, and stands at the origin of the great stone arch bridges built mainly in Oita and Kumamoto from the mid-nineteenth century.
What to Look For
Look at the near-semicircular arch of 25.1 metres and the tuff parapets (Agency for Cultural Affairs).
Visiting
The bridge spans the boundary between Usuki and Bungo-Ono. No official visiting information was found.
Q&A
- When was it built?
- From 1821 to 1824 (Agency for Cultural Affairs).
- How big is it?
- 31.0 metres long, 6.1 metres wide, with a 25.1-metre span.
- Why is it important?
- It had Japan's longest stone span and began the great stone arches of Kyushu.
- Where is it?
- On the Mie River between Usuki and Bungo-Ono, Oita Prefecture.
- When was the Kokan Bridge designated an Important Cultural Property?
- On December 1, 1999 (Agency for Cultural Affairs).
Basic Information
| Name | Kokan Bridge (虹澗橋) |
|---|---|
| Location | Notsumachi Nishihata, Usuki City, and Miemachi Sugo, Bungo-Ono City, Oita Prefecture |
| Designation | Important Cultural Property (Structure) |
| Year Designated | Designated 1999/12/01 (Heisei 11) |
| Quantity | 1 structure (with 1 stone monument) |
| Dimensions | Single-arch stone bridge with parapets, 31.0 m long, 6.1 m wide |
| Owner | Usuki City and Bungo-Ono City |
| Public Access | No official visiting information |
References
- Kokan Bridge (Database of National Cultural Properties, Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/heritage/detail/102/3672
Last verified: 2026.10.21