Japan's Only Surviving Lenticular Truss
The Minamikawachi Bridge (南河内橋) is a road bridge of 1926 in Kawachi, Yahatahigashi Ward, Kitakyushu City, Fukuoka Prefecture, and was designated an Important Cultural Property on December 19, 2006 (Agency for Cultural Affairs).
The Agency records a two-span steel truss bridge 133.0 metres long and 3.6 metres wide, with one concrete pier and two abutments with wing walls; designation number 02499.
A Road Bridge over the Kawachi Reservoir
The Minamikawachi Bridge, completed in November 1926, is a road bridge on the upper Okura River in Kitakyushu (Agency for Cultural Affairs). It crosses the Kawachi Reservoir, built to secure water for the state-run Yawata Steel Works.
It is a through-type two-span steel lenticular truss bridge 133 metres long and 3.6 metres wide (Agency for Cultural Affairs). It was designed by Nishijima Saburo, a technician of the steel works, under the direction of the works engineers Numata Naonori and Adachi Motojiro.
Why It Is an Important Cultural Property
It is valuable as one of the few steel bridges designed and built directly by the former Yawata Steel Works, the centre of Japan's steel industry (Agency for Cultural Affairs). As a lenticular truss of rational, clear construction it is the only one of its era left in Japan, and of high value to the history of bridge engineering. It was designated an Important Cultural Property on December 19, 2006.
A Lens-Shaped Truss
Each main span of 66 metres pairs an upright and an inverted curved-chord truss into a spindle shape, with verticals hanging the deck: an unusual structural form (Agency for Cultural Affairs). Every panel point is pin-jointed.
Kitakyushu City describes it as the only surviving bridge in Japan of the lenticular truss type, whose girders take the shape of a lens.
What to Look For
Look for the spindle-shaped trusses formed by upright and inverted curved chords, and the verticals that hang the deck (Agency for Cultural Affairs).
Visiting
It is a road bridge owned by Kitakyushu City, and no official information on visiting or access was found.
Q&A
- When was the Minamikawachi Bridge built?
- It was completed in November 1926 (Agency for Cultural Affairs).
- What type of bridge is it?
- A through-type two-span steel lenticular truss.
- Who designed it?
- Nishijima Saburo, under Numata Naonori and Adachi Motojiro.
- How long is it?
- 133 metres long and 3.6 metres wide.
- When was the Minamikawachi Bridge designated an Important Cultural Property?
- On December 19, 2006 (Agency for Cultural Affairs).
Basic Information
| Name | Minamikawachi Bridge (南河内橋) |
|---|---|
| Location | Kawachi 3-chome, Yahatahigashi Ward, Kitakyushu City, Fukuoka Prefecture |
| Designation | Important Cultural Property (Structure) |
| Year Designated | Designated 2006/12/19 (Heisei 18) |
| Quantity | 1 building |
| Dimensions | Two-span steel truss, 133.0 m long, 3.6 m wide; with 10 drawings |
| Owner | Kitakyushu City |
| Public Access | Access not confirmed |
References
- Minamikawachi Bridge (Database of National Cultural Properties, Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/heritage/detail/102/00004164
- Minamikawachi Bridge (Kitakyushu City, Japanese)
- https://www.city.kitakyushu.lg.jp/yahatahigashi/w5100051.html
Last verified: 2026.10.18