The fabric is produced using the old-style "loopwheel" knitting machine that was mainstream until the 1960s. This machine, which still exists mainly in Wakayama Prefecture, is suspended from the ceiling in a cylindrical form and is constructed so that the fabric is knitted slowly without applying unnecessary tension to the yarn, advancing only by the weight of the knitted fabric. Its production speed is extremely low, at about one meter per hour.
This technique maximizes the yarn's natural softness and texture, creating a unique, plump volume as if air were knitted into the fabric. The fabric, knitted on principles close to hand knitting, is supple and richly elastic.
It is characterized by excellent elasticity and high durability. Because it is knitted in a relaxed state, it resists hardening and losing shape even after repeated wear and washing, and its texture endures for a long time. A further characteristic is that it becomes more comfortable on the body the more it is worn, and the fabric develops greater character.
Due to low production efficiency and the decline in craftsmen capable of operating these machines, it is extremely rare and is known as a material that combines the warmth seen in vintage garments with timeless quality. The charcoal is dyed with sumi ink.