What is Sayashi in Japanese Katana terminology?

A "鞘師" (Sayashi) is a craftsman who creates the wooden sheath, known as "白鞘" (Shirasaya), for storing the blade of a sword. Utilizing their skills in making Shirasaya, they also prepare the base of the sheath and handle for "拵" (Koshirae), which is finished with lacquer, before it is decorated. The Koshirae is a type of mount used for the Japanese sword when it is being worn or used, as opposed to the Shirasaya which is used for storage. The Sayashi's work is crucial in the sword-making process as it not only protects the blade, but also contributes to the overall aesthetics and functionality of the sword.