What is Sokui in Japanese Katana terminology?

"Sokui" (続飯) refers to a type of adhesive made by thoroughly kneading softly cooked rice. It is used as a glue when assembling a "Shirasaya" (白鞘), a type of plain wooden scabbard used for storing Japanese swords. The advantage of using Sokui is that it makes it relatively easy to split the scabbard when it is necessary to remove rust or other residues from the inside of the scabbard, and to restore it afterwards. Although modern chemical adhesives have stronger bonding power, they make it difficult to split and restore the scabbard, which is a drawback.