Japan's First Civil Engineering National Treasure "Tsujun Bridge" - Journey to a Living Heritage

Nestled in the mountains of Yamato Town, Kumamoto Prefecture, Tsujun Bridge is more than just a tourist attraction. This stone arch aqueduct bridge, completed 170 years ago in 1854, is a "living heritage" that continues to supply water to 100 hectares of farmland on the Shiraito Plateau. In September 2023, its historical and technical value was recognized, and it became Japan's first civil engineering structure to be designated as a National Treasure.

A Miraculous Bridge Born from Edo Period Wisdom

Tsujun Bridge was designed and built by Futa Yasunosuke (1801-1873), the local head administrator. To save farmers on the Shiraito Plateau suffering from chronic water shortages, he realized an innovative idea. This bridge, boasting impressive dimensions of 75.6 meters in length, 20 meters in height, and 27.3 meters in arch span, features a revolutionary design with three built-in stone water pipes that send water to higher elevations using the reverse siphon principle.

Construction involved 41 skilled stonemasons and over 30,000 local residents, taking approximately two years to complete. The stones were precisely processed, and joints were sealed with special plaster made from salt, pine needle juice, clay, sand, and slaked lime. This traditional technique created a robust structure that withstood the 2016 Kumamoto earthquakes.

Daily Spectacle at 1 PM - The Rainbow Bridge

The highlight of Tsujun Bridge is the approximately 20-minute water discharge that occurs daily at 1 PM from Thursday to Sunday, April through November. Water forcefully shoots from three discharge outlets in the center of the bridge, creating water columns over 20 meters high. On sunny days, beautiful rainbows appear in the mist, giving rise to its nickname "Rainbow Bridge."

While this water discharge originally served as a maintenance function to expel sediment from the water pipes, it has now become a spectacular show that captivates many tourists. To witness the discharge, visitors need to purchase tickets (500 yen for adults, 200 yen for children) at the Tsujun Bridge Viewing Terrace, limited to 300 tickets per day.

Rich Nature Surrounded by Important Cultural Landscape

The area surrounding Tsujun Bridge is designated as a National Important Cultural Landscape called "Tsujun Irrigation and Shiraito Plateau Terraced Rice Fields." This was Japan's first national-level certification for terraced rice fields, representing a precious region that preserves traditional Japanese rural landscapes.

Goroga Falls, just a 10-minute walk away, is a magnificent 50-meter waterfall with breathtaking views from the suspension bridge. At Soyo Gorge on the border of Kumamoto and Miyazaki prefectures, visitors can enjoy kayaking experiences. The Seiwa Bunraku Theater, Kyushu's only dedicated puppet theater, offers performances of traditional arts.

Access and Best Season for Tourism

It's about 40 minutes by car from Kumamoto City, with the Kyushu Central Expressway "Tsujun Bridge IC" being the nearest interchange. If using public transportation, it takes about 1.5 hours by Kumamoto Bus from Sakuramachi Bus Terminal.

The best season is autumn (September to November), especially from mid to late September when spider lilies bloom, perfect for photography. Each season offers its own charm: cherry blossoms in spring, fresh greenery and rice planting festivals in summer, and the serene appearance of the bridge in winter.

Overcoming Disaster - An Indomitable Cultural Heritage

Despite suffering significant damage from the 2016 Kumamoto earthquakes and 2018 heavy rains, Tsujun Bridge achieved complete restoration in July 2020 through careful repair work using traditional techniques. This revival story is testament to the local residents' deep attachment to the bridge and their strong will to preserve cultural heritage.

Even today, a cooperative of local farmers manages daily operations, and the maintenance system that has continued since the Edo period remains functional. During the annual rice planting festival in June, the community comes together to carry on traditions.

A Living Heritage for Future Generations

Tsujun Bridge is not merely a historical structure but an active irrigation facility that continues to support local agriculture and livelihoods. With its National Treasure designation, its value has been reaffirmed, and a balance between proper preservation and utilization is being achieved.

Visitors are not only moved by the spectacular water discharge but can also experience the excellent civil engineering technology of the Edo period and the ongoing efforts of local people to preserve it. Tsujun Bridge is an irreplaceable treasure where Japan's traditional technology and culture continue to thrive in the modern era.