About Ply-joining "umu"
"Umu"=ply-joining and "tsumugu"=spinning
It is called "umu（績む）" in Japanese to make yarn by connecting fibers of plants and trees such as ramie, kudzu, hemp, linden or mulberry etc. They are obtained in ribbon shape, stiff and long, have to be split into thin pieces and then joined into yarn by hand; the tip of the fiber is attached to the end of another and twisted together. The finished yarn is flat and often twisted before being woven so that it get more durable, while it can also be directly woven into fabrics. This yarn making process is usually translated into English as "ply-joining".
On the other hand, spinning - to draw out and twist fibers into yarn - is called "tsumugu（紡ぐ)". Flax, cotton or wool can just be spun into yarn since these fibers are soft, hairy and easily get tangled.
"Umu"=ply-joining process used to be common in Japan; ordinary people could get only fibers of plants as mentioned above to make their everyday clothes or other textile products. Some people raised silkworms, but silk fiber was not ply-jointed but spun or reeled and clothes woven with them were luxury, not available for them.
The word "umu" and the process, however, are now rarely known and "tsumugu"=spinning is much more familiar to Japanese when it comes to making yarn; it's because cotton cultivation spread widely in Japan around 16th and 17th century - as you know, it is spun into yarn. Since spinning is clearly more efficient than ply-joining, cotton fiber replaced most of the other plant fibers as clothing materials - except in mountainous areas where cotton can't grow. In the modern age, all of the natural fibers are spun into yarn with machines, and ply-joining has mostly faded into oblivion.
*Some says "tsumugu" speaking of twisting flat ply-jointed yarn in order to give it the strength. So "tsumugu" may means just twisting yarns, not only draw out and twist fibers into yarn.
*I heard that people uses the word "tsumugu" in other way in silk industry.
In stillness
Ply-joining is the repetition of simple works: split fibers with fingernails, join the fibers into a yarn. Feeling the rough surface of natural fiber on fingers and lips, I twist them with the right hand, then with the left hand, and put the jointed yarn into a container. As I concentrate on fibers alone in silence aiming to make smooth and beautiful yarn, my heart quiet down which had been noisy and stormy in hectic everyday life. The moment of yarn making is like a lull, the moment I search my heart deeply.
The yarn made by hand in stillness has delicate nuances which can't be obtained with machines. Subtle differences of width made by hand, of stain, color and luster of fiber itself - they give power and beauty to even a coarse, simple and plain cloth.
So I love ply-joining: the moment concentrating on fibers, yarn - and myself. I will always appreciate this moment, the precious moment like meditation.