Koyama Sluice Gate is a historic three-arch brick water gate in Matsudo City, Chiba Prefecture. Built in 1898, during the Meiji period, it was originally constructed to prevent the Sakagawa River from being flooded by reverse flows from the Edo River.
The water gate is no longer used for its original flood-control function. Today, the historic structure forms part of a road bridge on Chiba Prefectural Route 5, the Matsudo-Noda Line. Locally, it is affectionately known as the “Brick Bridge” or “Megane Bridge,” meaning “Spectacles Bridge”, because of the distinctive shape of its three arches.
Koyama Sluice Gate is particularly valuable as one of the oldest surviving brick water gates in Chiba Prefecture and offers a fascinating glimpse into the development of modern Japanese civil engineering.
The Koyama Sluice Gate features a beautiful three-arch structure built in a British-style brick construction. Its elegant appearance is combined with the strength required of a hydraulic engineering structure.
The bricks used in the construction were produced domestically at a brick factory operated by the Terada Kanbe family. The factory was run by Goemon Yagihara, the former mayor of Kogane Town, who played an important role in flood-control projects in Matsudo. The bricks bear the same maker’s mark found on those used for the nearby Yanagihara Water Gate, providing an interesting connection between the two historic structures.
The brick bridge measures approximately 7.9 meters across the river on the upstream side and about 8.5 meters on the downstream side. In the direction of the river, its height is approximately 13 meters, while the wing walls extend about 3.5 meters.
The structure contains three water channels, each approximately 1.9 meters wide and 2.4 meters high. These substantial dimensions demonstrate the level of engineering technology available in Japan during the Meiji period and contribute to the structure’s significance as a modern civil engineering heritage site.
Koyama Sluice Gate was constructed in 1898 to prevent reverse flow in the Sakagawa River. Because the Sakagawa is connected to the Edo River system, controlling water movement was an important part of flood management in Matsudo.
The sluice gate was therefore one of the important water-control structures serving the area. Although it has since completed its original role and now functions as part of a road bridge, its historical significance remains visible in its preserved brick arches.
Koyama Sluice Gate stands at a point along the Sakagawa River where the river comes particularly close to the Edo River. The surrounding area is also associated with important historical sites, including Todaitei, the former residence of Tokugawa Akitake, the last lord of the Mito Domain, and the Todaitei History Museum of Matsudo.
The water gate was built six years before the Yanagihara Water Gate, which was completed in 1904. It is also approximately ten years older than the surviving Obagawa Lock Gate in Tokyo’s Mizumoto Park. These comparisons help illustrate the early date and historical importance of Koyama Sluice Gate.
During plans for river improvement, demolition of the Koyama Sluice Gate was once considered. During heavy rainfall and flooding, concerns were raised that the bridge piers could obstruct the flow of water.
However, as part of the Sakagawa River Restoration Project, a decision was made in 1997 to preserve the historic structure. Local efforts helped prevent its demolition and allowed this important example of Meiji-period engineering to survive.
In 2016, Koyama Sluice Gate was selected as a Heritage of Civil Engineering by the Japan Society of Civil Engineers, formally recognizing its historical and technological importance.
Koyama Sluice Gate is regarded as the oldest surviving brick water gate in Chiba Prefecture. Brick hydraulic structures from this early period are relatively rare in Japan, making the gate an especially valuable example of modern civil engineering heritage.
Its British-style three-arch design also demonstrates how Japanese engineers incorporated overseas construction techniques during the modernization of Japan. At the same time, the use of locally produced bricks connects the structure to the development of industry and infrastructure in the Matsudo area.
The gate also forms an important part of the history of flood-control efforts in Matsudo. Its survival allows visitors to see how engineering structures once used to protect communities can become historical landmarks in their own right.
Koyama Sluice Gate is an interesting destination for visitors who enjoy historic architecture, engineering, and local history. The three graceful brick arches provide a distinctive visual landmark, while the surrounding river landscape offers a pleasant setting for a short walk.
The nearby Todaitei and Todaitei History Museum of Matsudo can also be visited as part of the same outing. Combining these sites provides a broader introduction to the history and culture of Matsudo, from the world of the former Mito Domain to the development of modern infrastructure.
Koyama Sluice Gate is conveniently located within Matsudo City and can be reached by public transportation, followed by a short walk or bus ride from the nearest station.
The area can also be accessed by car, with parking facilities available nearby. This makes the site relatively easy to include in a sightseeing itinerary for visitors exploring Matsudo and its historic attractions.
Koyama Sluice Gate is more than a historic brick bridge. Its elegant three-arch design, early construction date, and role in the flood-control history of Matsudo make it an important example of Japan’s modern civil engineering heritage.
Built in 1898 and preserved for future generations, the structure provides a tangible connection to the technological changes of the Meiji period. A visit offers travelers an opportunity to discover a quieter side of Matsudo while appreciating the craftsmanship and engineering knowledge embodied in this historic brick water gate.