Japanese tissue

Tissue made from kōzo, or kōzogami (楮紙), comes in varying thicknesses and colors, and is an ideal paper to use in the mending of books.

The majority of mending tissues are made from kōzo fibers, though mitsumata and gampi papers also are used.

Bundles of kōzo sticks are steamed in a cauldron, then stripped of their bark and hung in the sun to dry.

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.

After being beaten, it is common for the kōzo fibers to be mixed with neri, which is a mucilaginous material made from the roots of the tororo-aoi 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."

The sheet of paper is placed on a wooden board and dried overnight, then pressed the next day to remove water.

The mender will select a piece of Japanese tissue that closely matches the color of the paper being mended, and chooses a thickness (weight) suitable to the job at hand.

This is done by wetting the paper along the area to be torn and then pulling sideways with the fingers to separate the strip from the rest of the sheet of tissue, so that it will have feathered edges.

The fibers in these feathered edges will allow the tissue to have a firmer hold on the mended paper and also to blend in with it once dried.

Japanese tissue should be water torn in the same process as described above, in a width and length sufficient to cover the hinge of the book with about 3/8 inch extension over the sides.

The washi paper, as long as bamboo sticks and silk, is the most important material to build kites.