From their factory in the Kochi prefecture of Japan, Hidaka Washi produces tengujo, the world’s thinnest paper, which has been produced for more than 1000 years in the region. Hidaka Washi has done so since first opening their doors in 1949. There, workers soak the stems of mulberry trees (kozo) and then pound them into lumps of fibers. With the addition of all-natural neri, and then a drying process, these fibers cling to one another in an almost magical way—resulting in a page only a few fibers thick. Paper conservationists treasure tengujo as it can reinforce damaged archival works. Explore the process and its benefits in-depth at The New York Times.