'In high heels, it's quite difficult'

Ye Zi, 18, has been practicing tai chi since 2011, and on Tuesday she was asked to tutor a special guest: US first lady Michelle Obama.

"She asked me how to remain calm in front of a huge crowd, and I told her we close our eyes," said Ye, of Chengdu, Sichuan province.

During Obama's visit to Chengdu No 7 High School on Tuesday morning, Ye found herself among a dozen young women, led by a male teacher, in a demonstration of tai chi for their guest.