Japanese Tissue - How IT Is Made

How It Is Made

Japanese tissue paper is a handmade paper. The inner bark of the kozo plant is harvested in the fall and spring, with material from the fall harvest being considered better quality. Bundles of kozo sticks are steamed in a cauldron, then stripped of their bark and hung in the sun to dry. At this stage in the process, it is known as kuro-kawa, or black bark.

To make paper, the black bark must be converted into white bark. The stored black bark is soaked and then scraped by hand with a knife to remove the black outer coat. It is then washed in water and again placed in the sun to dry.

White bark is boiled with lye for about an hour, then left to steam for several more hours. At this point, it is rinsed with clear water to remove the lye. Then, it is stream bleached (kawa-zarashi). The fibers are placed in a stream bed around which a dam is built. Clean water is let in periodically to wash the fibers. Alternatively, the fibers may be bleached using a process called small bleaching (ko-arai). In this case, it is first placed on boards and beaten with rods before being placed in a cloth bag and rinsed in clear running water.

Impurities are removed after bleaching though a process known as chiri-tori. Any remaining pieces of bark, hard fibers or other impurities are picked out by hand or, in the case of very small pieces, by the use of pins. The remaining material is rolled into little balls and the balls are then beaten to crush the fibers.

After being beaten, it is common for the kozo fibers to be mixed with neri, which is a mucilaginous material made from the roots of the tororo plant. The neri makes the fibers float uniformly on water and also helps to "...slow the speed of drainage so that a better-formed sheet of paper will result." (Narita, p.45)

A solution of 30 percent pulp and 70 percent water is then mixed together in a vat. Neri may also be added to the vat. Nagashi-zuki, the most common technique for making sheets of paper, is then employed. The mixture is scooped on a screen and allowed to flow back and forth across the screen to interlock the fibers. This process is ideal for forming thin sheets of paper. The other technique for making paper, tame-zuki, does not use neri and forms thicker sheets of paper.

The sheet of paper is placed on a wooden board and dried overnight, then pressed the next day to remove water. After pressing, the sheets are put on a drying board and brushed to smooth them. They are dried in the sun, then removed from the drying board and trimmed.