Thanks to decades of perseverance by traditional craftsmen, a 1,000-year-old wooden arch bridge in Ningde city, Fujian province, has managed to survive, and the skills used to make it have been adapted to modern life.

The bridge, which resembles a rainbow in outline, is a mortise and tenon structure built without using a single nail or rivet. A roof protects the bridge from weathering by the rain.

Eighty-five-year-old Huang Chuncai learned how to build the bridges from his father and grandfather when he was 15. By the time he was 20, he was skilled enough to become a chief designer.

When Huang mastered the traditional skill in 1969, however, there were no opportunities to put it into practice, as modern bridges were taking the place of wooden ones.

Instead, he earned his living making wooden furniture and threshing machines until the National Cultural Heritage Administration researchers came to Ningde in 2003 and tried to revive the craft.

Ningde, which is located near the coast of the East China Sea, is an area of ridges and ravines crisscrossed by streams. It is home to more than 50 wooden arcade bridges, some of which have stood for hundreds of years.

In 2008, the technique of wooden arch bridge building was listed as a national intangible cultural heritage, and Huang was designated as the skill's national inheritor.

"Over the years, my father continued drawing designs of arch bridges. He intended to leave a paper record of the craft. Before him, nearly nobody did that," said Huang Minhui, Huang's 38-year-old son.

Huang Chuncai has tried to pass on his skill, and he used to teach students at art schools in Ningde. "But many could not endure the difficulties and left," Huang Minhui said.

So far, about six students are training at a workshop set up by Huang Chuncai. "I hope the craft will endure. Our workshop welcomes anyone who wants to learn," Huang Chuncai said.

Huang Minhui returned to Ningde's Pingnan county from Shenzhen, Guangdong province, in 2005 to work with his father and elder brother on the renovation of old bridges and build new traditional-style arch bridges.

He quit his printing business because he felt the craft of traditional bridge building was a more promising career. His father had also urged him to return a number of times.

"I didn't learn the skill handed down by generations of my family at first because there was no way of using it. Now, the local government is emphasizing the protection and passing down of the craft so we are taking on projects to build traditional bridges and pavilions in scenic spots," he said.

Since 2005, Huang Chuncai and his sons have built dozens of wooden arch bridges in Pingnan.

One of their creations, the Shuanglong Bridge, which is located in a geological park in Ningde, spans 66 meters over a river valley at a height of about 10 meters.

"Mastering the skill mainly depends on personal experience rather than theory. The blueprint must be precisely calculated. For example, radians (a unit of angle equal to an angle at the center of a circle whose arc is equal in length to the radius) must be the same on both sides. Otherwise, the bridge will collapse," Huang Minhui said, adding that learning takes physical strength and endurance.

"It is all about dealing with large pieces of wood. Our construction sites are often dangerous because we build bridges in mountainous areas where there are no shops or shelters."