Bake the thread. The cotton thread that is the material is a baked thread.High-quality Supima cotton thread lets you pass thread a it in the fire and bake. it must not overbake. If the thread is overbaked, the thread itself will catch fire, and there is a danger that the raw material will be completely burnt. The factory is located in the mountains of Kawachi, Osaka. Toyotashigyo, a veteran of this industry for 70 years, has a rough but delicate technique. The flame burns off useless fluff and impurities and tightens the thread. As a result, the woven fabric is lustrous, and bright colors can be produced by dyeing. In addition, the durability improves because the threads are tightened by baking. A mysterious and extremely dangerous feat. A method that has been used in this country for over 100 years is called Gas Singeing  process. Few people know. The cotton thread that has been thoroughly Gas Singeing  process is sent into the kiln, where it undergoes a stable process called Heat set processing under high temperature and high pressure. After Heat set processing, leaving it to rest for several days also affects the subsequent quality. Careful skill is required.
These three process have created unprecedented cotton fabrics.