Daiichi Daidogawa Bridge: A Pioneering Landmark in Japanese Civil Engineering
Nestled in the forested valley of Shigaraki in Koka City, Shiga Prefecture, the Daiichi Daidogawa Bridge (第一大戸川橋梁) spans the Daido River as part of the Shigaraki Kohgen Railway line. Completed in 1954, this unassuming concrete railway bridge holds an extraordinary distinction: it is Japan's first full-scale prestressed concrete (PC) railway bridge. Designated as a national Important Cultural Property in 2021, the bridge continues to carry trains to this day, serving as both a working piece of infrastructure and a monument to postwar engineering innovation.
A Bridge Born from Disaster
The story of the Daiichi Daidogawa Bridge begins with catastrophe. The original bridge on this site was a three-span steel plate girder structure built when the Japanese National Railways (JNR) Shigaraki Line opened in 1933. In August 1953, a devastating flood caused by torrential rains in the Tarao area swept the old bridge away entirely.
When engineers set out to rebuild, they faced a critical challenge: the new bridge had to withstand future flooding. The decision was made to construct a single-span bridge with no intermediate piers in the river, requiring a clear span of 30 meters. At the time, prestressed concrete bridges of this scale were virtually unknown in Japan, and even worldwide, there were very few examples of PC railway bridges of comparable length.
Franco-Japanese Engineering Collaboration
The bridge's design drew upon cutting-edge European expertise. French engineer Serge Cobanico provided the fundamental design concept, which was then adapted into a detailed construction plan by Iwao Nisugi, then Deputy Director of the JNR Osaka Construction Office, and his team. They employed the Freyssinet post-tensioning method, threading high-strength steel cables through four I-shaped concrete girders and tensioning them to create the prestressed structure.
The resulting bridge has a total length of 31 meters with a clear span of 30 meters and a width of 4 meters. The girder height at the center of the span is just 1.3 meters — remarkably slender for a railway bridge designed to support heavy steam locomotives weighing over 100 tons. Concrete rocker bearings were adopted for the supports, and reinforced concrete wing walls were added on both sides of the abutments to protect against floodwaters.
Why It Was Designated an Important Cultural Property
The Daiichi Daidogawa Bridge was first registered as a national Registered Tangible Cultural Property in 2008 under the name "Shigaraki Kohgen Railway Daiichi Daidogawa Bridge." In 2021, the Council for Cultural Affairs recommended its elevation to the status of Important Cultural Property, which was officially designated on August 2, 2021.
The bridge is recognized for several key reasons. It represents the finest civil engineering technology of its era, bringing together international design expertise and Japanese construction skill to create Japan's first practical PC railway bridge. The extensive research and testing conducted during its construction laid the foundation for the subsequent widespread adoption of prestressed concrete in bridge building across Japan. Furthermore, the bridge has maintained its original condition remarkably well for over seven decades and continues to serve as an active railway bridge — a testament to both its design and the quality of its construction.
Highlights and Points of Interest
Visitors approaching the bridge from Gyokukeiji-mae Station will find it just a three-minute walk to the north. The bridge can be viewed from the riverside road that runs alongside the Daido River, offering clear views of the structure's elegant single-span silhouette against the surrounding mountain scenery.
One particularly noteworthy feature is the test specimen (standard girder) placed near the bridge's northeastern side. This companion piece was cast using the same concrete mix and dimensions as the bridge itself and has been exposed to the same environmental conditions since 1954. It serves as a reference for monitoring the long-term aging and durability of the bridge — an unusually forward-thinking approach for its time.
The bridge is still in active use on the Shigaraki Kohgen Railway, which operates approximately 15 round trips daily. Watching a single-car diesel train rumble across this historic structure over the clear waters of the Daido River is a memorable experience that connects the past with the present. An information panel and explanatory display have been set up near the bridge for visitors.
The Shigaraki Kohgen Railway Experience
A visit to the Daiichi Daidogawa Bridge pairs naturally with a ride on the Shigaraki Kohgen Railway itself. This charming single-track line runs 14.7 kilometers from Kibukawa Station (connecting to JR Kusatsu Line) to Shigaraki Station, traversing a dramatic landscape that includes steep gradients of up to 33 per mille and winding curves through forested mountains. The full journey takes about 24 minutes.
Along the route, you will pass through the historic land of Shigaraki, known for its ceramic tradition designated as a Japan Heritage site. At Gyokukeiji-mae Station, where you alight for the bridge, the retro-styled waiting area — renovated in 2022 through crowdfunding — evokes the atmosphere of the Showa era, complete with vintage-style lanterns and nostalgic decorations inspired by the NHK television drama "Scarlet," which was set in this area.
Nearby Attractions
The Shigaraki area surrounding the bridge offers a wealth of cultural and artistic experiences. MIHO MUSEUM, designed by renowned architect I.M. Pei with a "Shangri-La" concept, houses approximately 3,000 works spanning ancient Egyptian, Greek, Roman, Asian, and Japanese art. The museum is about a 20-minute taxi ride from Shigaraki Station.
The Shiga Prefectural Ceramic Art Forest (Togeino Mori) is a ceramics-themed park featuring an art museum specializing in pottery, a Shigaraki ware exhibition hall, an international artist-in-residence studio, and outdoor sculpture installations set amid verdant hills. Admission to the park grounds is free.
History enthusiasts will appreciate the nearby Shigaraki-no-miya Palace Ruins (紫香楽宮跡), the remains of a temporary capital established by Emperor Shomu during the Nara period in the 740s. The ruins are a designated national Historic Site and are accessible from Shigarakiguushi Station on the same railway line.
Gyokukeiji Temple (玉桂寺), the temple that gives the nearest station its name, is reached by crossing a suspension bridge over the Daido River from the station. This historic temple is known for its connection to prayers for good mental health and longevity.
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Q＆A
- Can I see the bridge up close?
- Yes, you can view the bridge from the riverside road near Gyokukeiji-mae Station. An information panel and display are located on site. However, please do not enter the railway tracks or restricted areas for safety reasons.
- Is there an admission fee to see the bridge?
- No, the bridge can be viewed freely at any time. It is located along a public road beside the Daido River.
- How do I get to the bridge by public transportation?
- Take the Shigaraki Kohgen Railway from Kibukawa Station (JR Kusatsu Line connection) and alight at Gyokukeiji-mae Station. The bridge is approximately a 3-minute walk north of the station. There is no parking lot at the site, so public transit is recommended.
- Is the bridge still in use?
- Yes, the Daiichi Daidogawa Bridge is an active railway bridge carrying trains on the Shigaraki Kohgen Railway. Approximately 15 round trips operate daily. You can watch trains cross the bridge during your visit.
- What is the best season to visit?
- The bridge can be enjoyed year-round. Spring brings fresh greenery along the Daido River, while autumn offers beautiful foliage framing the bridge. The surrounding Shigaraki area is particularly pleasant in spring and autumn when MIHO MUSEUM is open.
Basic Information
| Name | Daiichi Daidogawa Bridge (第一大戸川橋梁) |
|---|---|
| Cultural Property Designation | Important Cultural Property (designated August 2, 2021) |
| Location | Chokushi, Shigaraki-cho, Koka City, Shiga Prefecture |
| Owner | Koka City |
| Completion | August 26, 1954 |
| Design | Basic design by Serge Cobanico (France); detailed design by JNR Osaka Construction Office (Iwao Nisugi et al.) |
| Structure | Post-tensioned prestressed concrete single-span girder bridge (Freyssinet method), 4 I-shaped main girders |
| Dimensions | Total length: 31 m; Clear span: 30 m; Width: 4 m; Girder height at center: 1.3 m |
| Railway | Shigaraki Kohgen Railway, Shigaraki Line (between Chokushi Station and Gyokukeiji-mae Station) |
| Access | Approximately 3 minutes on foot from Gyokukeiji-mae Station (Shigaraki Kohgen Railway). No parking available on site. |
| Contact | Koka City Board of Education, Historical and Cultural Properties Division — TEL: 0748-69-2250 |
References
- 第一大戸川橋梁 — Wikipedia
- https://ja.wikipedia.org/wiki/%E7%AC%AC%E4%B8%80%E5%A4%A7%E6%88%B8%E5%B7%9D%E6%A9%8B%E6%A2%81
- 信楽高原鐵道の第一大戸川橋梁が重要文化財に — 甲賀市
- https://www.city.koka.lg.jp/16268.htm
- 第一大戸川橋梁 — 文化遺産オンライン
- https://bunka.nii.ac.jp/heritages/detail/542631
- 信楽高原鐵道第一大戸川橋梁 — 文化遺産オンライン（登録有形文化財時の記録）
- https://bunka.nii.ac.jp/heritages/detail/198209/2
- 信楽高原鐵道信楽線 — Wikipedia
- https://ja.wikipedia.org/wiki/%E4%BF%A1%E6%A5%BD%E9%AB%98%E5%8E%9F%E9%90%B5%E9%81%93%E4%BF%A1%E6%A5%BD%E7%B7%9A
- 第一大戸川橋梁 — PC技術についての報告（滋賀県構造物診断研究会）
- https://shiga-kouso.or.jp/relays/download/20/189/5/
Last verified: 2026.03.25