Oike No. 1 Bridge: A 1933 Girder Span Carried on Seven-Meter I-Beams
Where the Kishigawa Line reaches the pond called Oike, the rails cross on a low steel bridge 36 meters long, built as five girder spans set end to end. It carries a single track, and the girders are plate I-beams seven meters in length, paired side by side and tied together by lateral bracing above and below and by intermediate struts between them. Seven meters is a long run for a rolled I-beam, and that length is the detail engineers single out, because the standard bridge designs used by Japan's government railways in the early Showa years did not call for beams this size.
The bridge dates to 1933, when the line was pushed east from Idakiso to its present terminus at Kishi. It was built for the former Wakayama Railway, the company that operated the route at the time, and it has carried trains across the water ever since.
Why It Is Registered
In 2014 the bridge was added to the national register as a Registered Tangible Cultural Property. This category, introduced in 1996, is lighter than the Important Cultural Property designation and is intended to protect structures of the modern era, including the civil-engineering works that shaped the country's railways and roads, while keeping them in use.
Oike No. 1 Bridge was registered under the criterion of being difficult to reproduce. The unusual choice of long I-beams, departing from the standard government-railway pattern of the period, marks it as a piece of private-railway engineering with its own character rather than a stock design. It is registered together with two other bridges on the line, the longer Oike No. 2 Bridge a short distance away and the older Nishi No. 2 Bridge to the west, along with the inspection shed and platform at Idakiso Station.
What to Look For When You Visit
The most direct way to experience the bridge is to ride across it. As the train slows toward the crossing, the rhythm of the five short spans is easy to feel, and the water of Oike opens out on either side. From the bank, the low profile of the bridge sitting close to the surface of the pond makes the paired I-beams and their bracing clearly legible.
The bridge sits on the 1933 section of a line that first opened in 1916 to serve pilgrims bound for three shrines along the valley. The route became known well beyond Japan after a cat named Tama was appointed stationmaster at Kishi in 2007, and the colorfully themed trains designed by Eiji Mitooka run over this bridge on their way to the terminus. A one-day pass bought at Wakayama or Idakiso makes it easy to ride the full line and take in all three of its registered bridges.
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Q&A
- How can I see the bridge?
- The simplest way is to ride the Kishigawa Line across it. It can also be viewed from public ground near Oike, but as it is an active railway bridge, do not enter the track or the railway property.
- What makes a "five-span girder bridge"?
- It is a bridge whose deck is carried on five separate girder sections placed end to end, each resting on supports. Here the girders are paired steel I-beams about seven meters long.
- Why are the long I-beams significant?
- Beams of this length were not part of the standard bridge designs used by the national railways in the early Showa period, so their use here reflects a distinct engineering choice by the private railway that built the line.
- Where is it on the line?
- It lies east of Idakiso on the 1933 extension toward Kishi, crossing the pond of Oike near the boundary of Wakayama City and Kinokawa City. The neighboring Oike No. 2 Bridge crosses the same water.
Basic Information
| Name | Wakayama Electric Railway Kishigawa Line, Oike No. 1 Bridge |
|---|---|
| Location | Nagayama, Wakayama City to 1304-3 Nagayama, Kishigawa-cho, Kinokawa City, Wakayama Prefecture |
| Designation | Registered Tangible Cultural Property (registered 25 April 2014; registration no. 30-0186) |
| Built | 1933 (Showa 8) |
| Count / Scale | 1 structure; steel five-span girder bridge, length 36 m, single track; girders of 7 m I-beams |
| Owner | Wakayama Electric Railway Co., Ltd. |
| Access | On the Kishigawa Line east of Idakiso Station. Best experienced by riding across; active railway bridge, do not enter railway property. |
References
- National Database of Designated Cultural Properties (Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/bsys/maindetails/101/00010035
- Wakayama Electric Railway Co., Ltd. official site
- https://wakayama-dentetsu.co.jp/
- Wakayama Prefecture, railways information
- https://www.pref.wakayama.lg.jp/prefg/020500/tetudou/tamadesu.html
Last verified: 2026.06.22