I was in Boston for a short trip and met up with my old friend Mary from Philadelphia, whom I haven't seen for a year. Over the weekend, she couldn't stop talking about tai chi.

I took my first English writing class from Mary 12 years ago. We have remained close friends ever since. She witnessed my various attempts to fit into American society, and I kept her company through her various heartbreaks. Still, her fascination with tai chi took me by surprise.

Mary grew up in the Midwest a pious and liberal Christian. After receiving her Ph.D in the humanities, she taught writing at university and was heavily involved in social work. Despite our great friendship, she would only smile politely each time I sent her books on Chinese history or invited her to visit China. What had suddenly drawn her to tai chi?

"You know that I went to Taiwan in 2008 for research on Eastern healing," said Mary. "I arrived in Taipei with my knee and back hurting badly. Dr Lin, my host, put me through acupuncture and the pain went away! He also suggested that I take up tai chi, as a way to change my lifestyle and my health."

After that trip, Mary started taking classes at a dance studio set up by a gay Taiwanese dancer in Philadelphia. The tai chi teacher, an Italian American from South Philly, also taught at the community center where most of the students were African-American and Muslim women with their veiled faces.

The South Philly teacher sent Mary, a slow but tenacious student, to his master. Coming from China, Master Ching belonged to the same generation as Jet Li and appeared in many of Jet Li's early martial-arts films. Now he runs a martial arts school in Philadelphia so he can educate his two kids in the US.