All of the cuju balls made in Yu's workshop are handmade. His cuju products have been sold to more than 130 countries and regions.

To protect and promote the manufacturing techniques of cuju balls and equipment, Yu provides courses for students who come to his workshop to study and try their hand at making cuju equipment, welcoming around 10,000 people every year.

Students in Linzi are not only learning how to make cuju equipment, but also playing the game as a form of exercise and to master the techniques of playing this ancient style of soccer.

"Side-flicking", "chest down "and "shoulder stopper" are some of the essential moves mastered by cuju players. Li Weipeng, a seventh-generation inheritor of cuju, has been practicing these skills for 18 years.

The 34-year-old is now perfect at different cuju techniques. However, when he joined the cuju team in 2004, he was stumped by the simplest of moves, even though he had been playing football for a decade.

Li had undergone professional football training since he was 8 years old. In 2004, when the cuju team in Linzi was looking to recruit players, he signed up.

"At the beginning, I spent eight hours a day practicing juggling a ball. It was exhausting," says Li.