According to Xu Chao, a professor of the National Academy of Chinese Theater Arts, 10 students, who are either students of the same academy or actresses of Peking Opera companies across the country, have studied with Zhang so far.

"The mission is to keep the art of Cheng school alive and popularize it among the young," says Xu.

"It's not only her performing techniques but also her attitude toward this art that has a profound effect on her students," Xu says of Zhang.

For Li, the years before she studied under Zhang were a struggle, and she even considered quitting her job as a Peking Opera actress since the 200-year-old Chinese art form was facing decline.

"I had no performances and most of my colleagues tried to find other jobs. I really doubted myself and was looking for a change," Li says.

She took lots of auditions to perform in different shows.

And in July 2013, she won the opportunity to play in a musical titled Monkey: Journey to the West, which is a stage adaptation of the Chinese novel Journey to the West written by Wu Cheng'en of the Ming Dynasty (1368-1644). The show opened that year during the Lincoln Center Festival in New York where Li spent six months.

"I lived in a fancy hotel and went to the theater every day. It was a totally different experience from being a Peking Opera actress. I made about 100,000 yuan ($15,750) from the musical, which was big money for me," recalls Li, who made about 2,000 yuan a month at Beijing Peking Opera Theater then.

After the musical, Li received some other opportunities to perform in Western stage productions but she decided to return to Beijing in 2014.

That year, Zhang announced her return to stage after a four-year hiatus and Li watched Zhang's sold-out show at Beijing's Chang'an Grand Theater.

"It was the longest standing ovation I've ever seen. The audience was asking when they could see her performance again. I felt then that I should not give up the art form," says Li. "Now I feel very calm and confident with this art."

In September 2015, when Zhang made her debut at the Lincoln Center for the Performing Arts in New York by performing two shows, The Jewelry Pouch and The Legend of White Snake, Li was there as Zhang's assistant. It was the same dressing room and the same stage that Li had used in the musical Monkey: Journey to the West.

"It reminded me of my days in New York in 2013 but I didn't miss them. Now I want to focus on Peking Opera," Li says.