Our tengu is used for strengthening archives that are seriously damaged by things such as worm-eating and iron gall ink. To prevent splitting, our thin and transparent tengu covers an entire record. As you can see, our tengu is transparent enough to retain a high degree visibility.
The National Archives of Japan uses our tengu to conserve records with a leafcasting machine. They put damaged records between sheets of tengu. Then set those in the leafcasting machine. This process strengthens the damaged records and fills in the missing sections of paper.