Its lyrics are based on southern Fujian dialects, and its musical instruments and melodies almost remain as they were 1,000 years ago.
Born in Quanzhou, a city near Xiamen, Cai grew up hearing these ancient melodies. Now, she has become a promoter of its musical tradition.
Cai worked for years in Singapore for a charity organization to promote Nanyin.
"Though Singapore has a huge Chinese community, Nanyin still was popular only among a small circle of people there," she said, explaining her return home.
"However, it used to be part of our everyday life. Other people deserve chances to enjoy our traditional culture, especially for young people." Cai threw all her savings into the promotion of Nanyin and only made ends meet through money from small-scale concerts. She joked that getting immersed in Nanyin has kept her feeling young.
"Who can be older than this 1,000-year-old music? When playing it, you always feel like a child," she said.
Traditional art forms do not necessarily help remove a person from modern life.
"Nanyin can be a social communication break for modern people - who are fed up with the fast-paced lifestyle - just like playing golf," she said. "When you gain a slow mood and inner peace through the music, you can also get more friends sharing your values."
Nevertheless, a wider horizon is needed to get traditional art revitalized, she said.