Watarase Keikoku Railway Edogawa Bridge

Watarase Keikoku Railway Edogawa Bridge: A Hidden Gem of Meiji-Era Railway Heritage

Nestled deep in the forested valleys of Kurohone-cho in Kiryu City, Gunma Prefecture, the Edogawa Bridge (江戸川橋梁) of the Watarase Keikoku Railway stands as a quiet yet remarkable testament to Japan's early industrial ambitions. This compact steel bridge, spanning just 5.6 meters across the Edogawa River, has carried trains through the mountains of northern Gunma since 1912 — connecting Japan's copper mining heartland to the wider world for over a century.

Designated as a Registered Tangible Cultural Property of Japan in 2009, the Edogawa Bridge is one of 38 railway structures along the Watarase Keikoku Railway that have been recognized for their cultural and historical significance. Together, they form one of the most comprehensive collections of early railway heritage in all of Japan.

The Story Behind the Bridge: Ashio Copper Mine and the Birth of a Railway

The Edogawa Bridge owes its existence to one of the most important industrial enterprises in Japanese history: the Ashio Copper Mine (足尾銅山). During the late 19th and early 20th centuries, Ashio was the largest copper mine in Japan, and the demand to transport vast quantities of ore to ports and processing centers drove the construction of the Ashio Railway (足尾鉄道).

The Ashio Railway Company was granted its operating license in January 1910, and construction began immediately. The first section of the line opened on April 15, 1911, linking Shimo-Shinden to Ōmamachi (now Ōmama Station). By 1914, the full 46-kilometer route from Kiryu to Ashio-Honzan was complete, threading its way through narrow river gorges and over countless bridges and through tunnels carved into the rugged terrain.

Over the decades, the railway changed hands multiple times — from the private Ashio Railway Company to the Japanese National Railways (JNR), then to JR East, and finally to the third-sector Watarase Keikoku Railway in 1989. Through all of these transitions, many of the original Meiji and Taisho-era structures have survived intact, continuing to serve the railway to this day.

Why the Edogawa Bridge Was Designated a Cultural Property

The Edogawa Bridge was registered as a Tangible Cultural Property of Japan on November 19, 2009, as part of a group of 37 railway structures along the Watarase Keikoku line (one additional station, Kamikambai Station, had been registered the previous year). The registration of railway facilities spanning two prefectures — Gunma and Tochigi — was a first in Japanese history, highlighting the exceptional heritage value of this railway corridor.

What makes the Edogawa Bridge particularly significant is the evidence of international industrial connections preserved in its steel. The bridge girders bear a maker's plate confirming they were manufactured in 1911 by the Kisha Seizo Goshi Kaisha (汽車製造合資會社), a pioneering locomotive and rolling stock manufacturer based in Osaka. Even more remarkably, the steel beams themselves carry the stamped markings of Dorman Long & Co., the legendary steelmaker from Middlesbrough, England.

Dorman Long was one of the great steel and engineering firms of the British Empire, later famous for constructing the Sydney Harbour Bridge and the Tyne Bridge. The discovery of their steel in this modest mountain railway bridge reveals how Japan's early railway infrastructure was built with materials sourced from the world's leading industrial centers — a physical connection between Teesside and the mountains of Gunma that endures to this day.

The bridge's rubble-stone abutments, its I-beam construction, and its cobblestone wing walls all preserve the original engineering methods of the Taisho era, making it an invaluable document of early 20th-century railway construction techniques in Japan.

Highlights and Points of Interest

The Edogawa Bridge is located southeast of the intersection of National Route 122 and Prefectural Route 62 (Numata-Ōmama Line) in the Shimotazawa area. It spans the Edogawa, a small river that flows into the Watarase River (渡良瀬川). While the bridge itself is somewhat difficult to observe from public vantage points due to the surrounding terrain and vegetation, it remains an essential part of the heritage narrative of the Watarase Keikoku Railway.

For visitors, the true appeal of the Edogawa Bridge lies in experiencing it as part of a larger journey along the Watarase Keikoku line. The bridge is situated between Mizunuma Station and the surrounding stops, and passengers riding the train will cross this historic structure as they travel through one of the most scenic railway corridors in the Kanto region.

Surrounding Area and Nearby Attractions

The Kurohone area of Kiryu City, where the Edogawa Bridge is located, offers a range of attractions that pair beautifully with a railway heritage visit.

Mizunuma Station (水沼駅), the nearest station, is famous for its onsen (hot spring) facility directly on the station platform — one of the few hot spring stations in Japan. Visitors can soak in the mineral-rich waters while waiting for their next train, making it a perfect stop on a leisurely journey along the line.

Further along the line, the Ashio Copper Mine Tourism Site (足尾銅山観光) near Tsūdō Station offers guided tours through former mining tunnels, providing fascinating context for why the railway was built in the first place. The nearby town of Ōmama features the Nagame Yokyōjō, a historic entertainment hall where kabuki performances were once held, as well as the scenic Takatsudo Gorge (高津戸峡).

For nature enthusiasts, the entire Watarase Valley offers outstanding hiking opportunities, river activities, and some of the finest autumn foliage viewing in the Kanto region. The area is also accessible from Nikkō via bus connections from Tsūdō Station, allowing visitors to combine a railway heritage trip with a visit to the UNESCO World Heritage shrines and temples of Nikkō.