On the internet, I stumbled upon an image of indigo and white stitch-resist cotton, and found that those heavier pieces I had bought in Arimatsu were probably from Yunnan. Following the textile trail, I traced zha-ran to the village of Zoucheng, and visited there in 2007 with the express purpose of solving the mystery of the little butterflies.
Here is a video of a local woman folding and stitching the cotton cloth in such a way that the enclosed fabric that will remain white emerges in the shape of a butterfly:
Many thanks to my long-suffering younger daughter, who accompanied me on this quest and took these step-by-step photos of me executing the butterfly stitch.
Prepare a needle with strong thread, knotting both ends together so you are stitching with a doubled thread.
Make a horizontal fold in the fabric. Create a point by folding twice more, in Z-fashion. The angle at the point is 30 degrees and your point will have 6 layers of fabric. Fold the point over toward you and take your needle through all 12 layers of fabric:
Thread emerging at the back:
Take the needle through again at the same place, in the same direction. Guide the loop that is created so it tightens slightly to one side of the fold (see both images):
Pull thread very firmly:
Take needle through for a third time. Begin in the same place at the front, but emerge slightly to one side. This will create the butterfly’s antennae:
Guide the loop around the needle:
Pull the needle through the loop, guiding the loop to one side so the threads creating the antennae resist are separated:
The two loops that will resist the dye to create the antennae (and make the rhomboid wings & body) are separated:
Pull the thread very firmly and break off the end (I can’t bear to do that, and cut it with scissors):
Your butterfly is ready for the dye-pot:
See a variety of completed zha-ran designs at Zha-ran Tie-dye
Learn more about the zha-ran stitch-resist process at Zoucheng: Zha-ran production