Raw Materials: From Bark to Paper Fiber
To prepare the plant fibers to make paper, the white inner bark (shirokawa) of the kozo (paper mulberry) tree is soaked in water, then boiled with soda ash for softening. The resulting fibers resemble silk. Impurities from the outer bark affect the appearance of the paper, so they are removed by hand in a process known as chiritori. The fibers are carefully rinsed and picked over under running water. Historically, chiritori was performed by workers crouching for hours over a stream, but modern papermakers sit at a raised tub supplied with running water. Experienced pickers can process 1 to 2 kilograms of fibers a day.
After removing the impurities, the papermaker pounds the clean fibers with two wooden mallets to separate the strands without significantly reducing their length through tearing or cutting. This is important because longer fibers create stronger, smoother paper. The tools for pounding vary by region, from long sticks to the thick mallets (kizuchi) used in Mino. They are made from sturdy pine, with a striking surface carved with a radial “chrysanthemum” pattern to efficiently separate the fibers and prevent strands from sticking to the face of the mallet.