The materials used to make Japanese paper

Japanese paper is primarily made from plants. Watch the video to see the main materials used in washi papermaking.

Plants used to make paper

The plants used to make paper differ by geographical area. Even within the same country, there is no single type of paper. There are differences by manufacturer and differences due to the different habitats of the plants used. Additionally, raw materials can be transported from place to place. Just like the text and images of a book, the paper it is made of carries a wealth of information about where, when and by whom it was made.

In Japan, plants containing bast fibres, which are sturdy and resistant, soon became the primary ingredient. Listed below are the most important plants in the order that they began to be used in papermaking:

Ramie (choma)

This perennial plant from the nettle family (Urticaceae) is variously known as choma, karamushi or mao (fig. 1) and is sometimes mentioned in classical Japanese poetry (waka). Its long fibres can be woven into the thread to make fabric. When used to make paper, they are cut.

^{fig.1. Boehmeria nivea (L.) Gaudich.}

Paper mulberry (kōzo)

The renowned kōzo (Brussonetia papyrifera, fig. 2) is a shrub of the Moraceae family. The most common type of washi was made from the bark of this plant. It is the paper used to print the famous Hyakumantō dharani (One Million Pagodas and Dharani Prayers, 770), Japan’s oldest printed text. Because it is easy to cultivate, it was widely used all across Japan.

^{fig.2. Broussonetia papyrifera (L.) L’Hér. ex Vent.}

Gampi (gampi)

The gampi (Diplomorpha sikokiana or Wikstroemia sikokiana, fig. 3) are a group of shrubs of the genus Wikstroemia. It is the main ingredient of the beautiful hishi paper. It is difficult to grow in cultivation, so it was considered extremely precious. It is thick and smooth which makes it suitable for writing on both sides; it was also used as tracing paper.

^{fig.3. Diplomorpha sikokiana (Franch. & Sav.) Nakai, alternatively Wikstroemia sikokiana Franch. et Savat.}

Mitsumata

The mitsumata plant (Edgeworthia chrysantha, fig. 4) belongs to the same genus as the gampi but unlike the gampi, it can be grown in cultivation. The paper is similar to gampi but not identical. Because close to 70% of Japan is covered by forest, the supply of raw materials was generally less problematic than in other areas, which allowed papermakers to experiment with new materials and production techniques virtually continuously since 700CE.

The use of Gampi and mitsumata as materials for papermaking, which is unique to Japan, was discovered at some point during this long process.

^{fig.4. Edgeworthia chrysantha Lindl.}

Neri

Plants are also the main ingredient to make neri, a starchy substance that is added to the pulp as a dispersant.

Tororoaoi

The most commonly used neri is made from the aibika plant (J. tororo-aoi, Abelmoschus manihot, fig. 5). The roots of the plant are pounded and soaked in water to obtain a viscous liquid. Because it is most effective as a dispersant at low temperatures, in cases when neri made from the aibika plant is used paper is made in wintertime.

Incidentally, this is also why in haiku poetry “papermaking” (kamisuki) is a “winter” seasonal word (kigo).).

^{fig.5. Abelmoschus manihot (L.) Medik. var. manihot alternatively Hibiscus manihot L. var. manihot}

Panicled Hydrangea

In some areas of Japan, the panicled hydrangea (J. noriutsugi, Hydrangea paniculata Siebold, fig. 6) was used as a substitute for aibika. Although less powerful as a dispersing agent than the aibika-based neri, noriutsugi is not affected by temperature variations so it can be used throughout the year.

^{fig.6. Hydrangea paniculata Siebold}

In some parts of Japan, neri is called nori which, confusingly, sounds identical to nori (glue, adhesive). The two are completely different substances used for different purposes and should not be confused. Neri (not nori) is used in the vat to separate the fibers and, later, to prevent the sheets of finished paper from sticking together. It is an important ingredient in the nagashizuki papermaking method.

If you’d like to learn more about the art of Washi paper in Japanese rare books, check out the full online course from Keio University, below.