Forming a continuous thread by joining the split fibers that have been wound into a ball (chingu) is called ply-joining (u-umi). The chingu ball is allowed to steep in a bowl of water for about thirty minutes and then squeezed. Next the fibers are split to the desired thickness with a small knife. This is most time consuming because the quality of the final bolt of cloth depends on the uniformity of the ply-joined threads.