That's where Xu, then in his late 20s, was given lessons by the old man while breathing in the chilly mountain air.
"For the purpose of fan-making, bamboo can neither be too young nor too old — it has to be big and sturdy enough while at the same time fine-textured. Generally speaking, plants that have grown to 5 years old are the most desirable," Xu says.
"One thing my father always asked me to look for was the natural layer of white, waxy substance coating the plant."
This is bamboo wax, and when scraped off, the green color underneath is revealed — thus it's known as "jade bamboo". The wax shields the plant from excessive moisture loss and pests, giving it a smooth, suave quality long admired by Chinese fan-makers including Xu and his father.