Production of Kozo Paper
Step 1: Boiling Kozo Plant Fibers
After the kozo plants are naturally dried, the first step in producing Tengujō Washi paper is boiling them in a large tank. Using clean, natural water from the region, the fibers are gently cooked to remove pectin and lignin. This process purifies and softens the fibers, preparing them for use as the raw material in papermaking.
Step 2: Washing to Remove Impurities
The fibers are then carefully washed to remove every single mote. This is one of the most important stages in the entire process, as any remaining impurities will not whiten—even if bleached—and will appear in the finished paper. To ensure complete purity, the fibers pass through five washing stations, each tended by a different craftsman, meticulously removing even the smallest imperfections.
Step 3: Bleaching Kozo Fibers
At this stage, the material is a reddish-brown color and must be bleached to achieve its characteristic whiteness. While chlorine is commonly used for bleaching, chlorine-treated paper can yellow over time. To preserve the paper’s natural clarity and long-term stability, we use our own chlorine-free bleaching method, ensuring the color remains unchanged.
Step 4: Mixing the Fiber and Water Ratio
The fibers are carefully mixed to ensure they are evenly dispersed throughout the water solution. The ratio of plant fiber to water is approximately 1:5, allowing the material to remain suspended rather than sink. At this stage, neri—a natural formation aid used to increase viscosity—is added, helping bind the fibers together and giving the mixture the body needed for papermaking.
Step 5: Specialized Machines Make Tengujō Paper
The prepared slurry then flows into the papermaking machine, which replicates the traditional hand-rocking technique once used to evenly intertwine the plant fibers. As the sheet forms, careful observation and precise adjustments are essential to control the thickness, size, and fiber distribution, ensuring consistency and the highest quality in the finished paper.
Step 6: Rolling Finished Tengujō Paper
The delicate, ultra-thin fibers are then formed and rolled into sheets, becoming the finished paper product. Composed primarily of cellulose, kozo fibers are highly absorbent and sensitive to handling. To preserve their strength and integrity, the sheets are carefully dried at a low temperature over the course of a week.