"Sometimes, the knife would glide through the material in an extended motion; other times, it makes quick, decisive cuts. Either way, there would be absolutely no repeat of the same movement. One has the feeling that the master, guided by his own instinct, always gets to say what he has intended to say with just one fluid and resolute stroke of the knife."

In that sense, there's not much difference between carving the fan ribs and painting a fan. The latter, done in classical Chinese style with an ink brush, is also characterized by a combination of precision and spontaneity.

"One thing my father taught me was to think of the knife as a brush," Xu says.

"In fan-making, polishing is routinely done to the carved ribs, but my father often reminded me not to overdo it. 'Don't gloss away all the traces of your knife', he would say. 'Because they are indicators of an authentic work of art'."