"The lessons were basically one on one," Xu recalled. "There was no systematic way of teaching, so we had to follow our masters very carefully."

To craft a good painting, it is important to understand the delicate strength when making the iron curves.

"Every detail requires extra attention," he said.

At first, Xu did not master the techniques, and his failures often frustrated him. However, he would spend hours learning until he owned the skills.

"It was boring. We mainly spent our time pounding the iron sticks to learn about precision," he recalled. "I needed to make sure that every hit pounded the thin iron wires."

Xu said he would beat the sticks thousands of times a day, and the practice lasted a month before he proceeded to design entire paintings.

"Because there were sparks everywhere, it was normal to get burnt," Xu said. "It was tiring, but I am glad I made it."

Xu said iron painters often have burns on their hands, and the fingerprints have almost disappeared on their thumbs, index fingers and middle fingers because they constantly bend the iron wires with their fingers.