Three generations of his family have been, in Yang Huixiang's words, "nearby carpenters". Today, Yang Shengchun himself is recognized as a provincial inheritor of the Dong people's traditional wooden construction techniques.
Tongdao's abundance of covered bridges, Yang Shengchun believes, is tied to geography. Located on the border between provinces, the area historically relied on rivers for trade. Some transactions even took place on the bridges themselves, where villagers would hang handmade straw sandals for travelers to borrow.
"The Dong communities are generous. They believe in doing good," he says. If the wood rotted or the roof leaked, villagers called for repairs. At times, carpenters worked without pay.
At the heart of the Dong covered bridges is the wooden mortise-and-tenon method. To guide the assembly of each component, craftsmen employ a secretive set of coded symbols known as moshiwen, often marked on bamboo sticks. These signs ensure that the wooden pieces interlock tightly and securely. Yang Shengchun notes that mastering the craft takes at least three years, a prerequisite for any bridge repair.
Beyond bridges, Yang Shengchun also builds traditional wooden homes for local families. He currently teaches more than 20 apprentices, most over the age of 50.
His young grandnephew, not yet 30, has become his main protege. As Yang Shengchun says, "I'm happy to teach anything I know to young people who are willing to learn."
Efforts to preserve China's covered bridges increasingly combine physical conservation with the protection of intangible heritage. After a devastating fire in 2022 destroyed Wan'an Bridge in Fujian province, reconstruction followed strict conservation principles, reusing original materials where possible and involving traditional craftsmen in the rebuilding.
In 2024, traditional designs and practices for building Chinese wooden arch bridges were transferred from UNESCO's List of Intangible Cultural Heritage in Need of Urgent Safeguarding to its Representative List of the Intangible Cultural Heritage of Humanity, underscoring the global concern for their survival.
International scholars have long taken an interest. Since the 1960s, American geographer Ronald G. Knapp has studied Chinese rural architecture. In his book, China's Covered Bridges: Architecture over Water, he argues that preservation in China need not follow Western models.
"All too often," he said in an interview, "the average person knows what is worth preserving, whereas architects, planners, and designers may not reflect the integrity of the original landscape."
Back in Tongdao, modern tools — from digital modeling to 3D scanning — are beginning to supplement traditional methods. But Yang Huixiang insists they cannot replace the intangible heritage of traditional bridge craftsmanship. "It still has to be passed down."
For Yang Huixiang, the principle of protecting covered bridges is simple: diligence.
"Cultural relic protection is not talk, but work — go to the site, see it for yourself, and build understanding on solid ground."
For Yang Shengchun, the lesson is equally clear, though rooted in a different mindset: humility.
"Skill is no mystery," he says. "Stay humble, practice more — there's nothing magical."