"When students tried to cut the meticulous patterns on a board, as one of the steps of making blue calico, they said 'it's too tiring'. But when they finally finished their pieces, they cherished them so much that they wanted to keep them and didn't want to hand them in as homework," says Ni.

Some of Ni's students, as fashion design majors, later used blue calico elements in their designs. Others who became teachers also used what they learned at Ni's lessons in their own classes.

To give blue calico a more modern context, Ni and his family have been trying to innovate the craft. For example, old blue calico was entirely cotton, but they changed the material used to create silk, woolen and linen examples. Some young people thought the blue color was too dark, so they changed the proportion of dyestuff and developed gradient blue calico.

Over the years, Ni has found his life busy but meaningful. "Some jobs can reward you with both fame and wealth, and people flock to do them. But for some others, if you don't do them, maybe nobody else will do so in the future," Ni says.

Our family are trying to keep the craft alive, he adds.