Can you imagine what is KIBISO(生皮苧=raw-skin-nettle)
The answer is a kind of silk fiber.
However, it would be far from your image about silk. Pre-refined KIBISO silk looks very wild like hemp palm and actually quite hard.
Not known to common, but when silkworms spin first, the fibers are covered with hard protein called sericin. That's why our ancestors put 苧-Chines character on its name though it originally means "nettle". Yes, its texture is exactly like nettle hemp.
When silkworm farmers get silk fibers from cocoons, they boil the cocoons and stroke the surface with a bamboo whisk to find the beginning.(From the beginning to the end of a cocoon, they wind about 1500m faber without a break.)
Before finding the true beginning of a long fiber, at the end of bamboo whisk many short waste fibers are stuck. Silkworm farmers gather these waste fibers and spin. This is KIBISO yarns.
Usually we weavers put off the sericin by boiling the fibers with soda to make it soft and shiny. But as I love raw KIBISO's wild and tough texture, I use this without refining. Very difficult to dye and weave, but really attractive!
When we touch hemp palm or hemp nettle, our hands get chapped. But KIBISO doesn't make our hands rough at all. On the contrary, it makes our skin smooth...!
You know we Japanese have countless monstrous creatures in folk tales. One of the famous creatures 苧うに(Ouni), which has same Chines character on name, is well known to have very hard disheveled long hair.(right photo) Looks exactly KIBISO!
I weave KIBISO cloth for Obi or bags time by time.