DALI VILLAGE, China — The young woman sat at the foot of the wooden loom and began to weave. As her fingers passed the orange shuttle back and forth through the delicate cotton threads, the creaky contraption sprang to life.

Yang Xiuying — a plucky woman no taller than the loom — peered over her granddaughter’s shoulder, inspecting the newly emerging fabric for flaws. Ever since she was a young girl, Ms. Yang, 74, has been weaving and dyeing indigo textiles using techniques that the ethnic Dong in the southern Chinese province of Guizhou have passed down from mother to daughter over generations.

“You can’t buy this type of handmade cloth at the market,” Ms. Yang said, patting a bolt of gleaming indigo-colored cloth with her wrinkled, navy-stained hands.