Silk refers to raw silk, which is the product obtained after reeling silk from mulberry silkworm cocoons. High-quality cocoons are placed in a cocoon boiling machine with hot water at 80°C to soften and fluff them. Then, a reeling device pulls out several strands of silk together and continuously winds them onto a reeling frame, a process known as "reeling." At this stage, the silk still contains about 20% sericin, and the lustrous silk fibers are coated with sericin, giving the silk a slightly hard and semi-transparent texture, known as "raw silk."