Skip to 0 minutes and 2 secondsEach plant fiber looks different and by identifying their distinctive features we can tell from which plant the paper was made. The most reliable way to do this is to use a microscope. The first experiments were conducted at the University of Vienna in 1887. Here, we will use the simplest modern method. Here I want to take a hands-on look at the plants from which books are made. Here we have a printed book dating from the second half of the 17th century and here is a handwritten book from the first half of the 17th century. Both are made of kōzo paper but if we look closely, they are different.

Skip to 0 minutes and 59 secondsThe late-17th century printed book is made of kōzo (paper mulberry) fibers.

Skip to 1 minute and 7 secondsThese long shapes you see on the screen are typical paper mulberry fibers.

Skip to 1 minute and 17 secondsHere is the early 17th century manuscript. As compared to the previous paper, the fibers are crushed and the three-dimensional appearance is lost because of the hammering technique (uchigami). Although it is made from kōzo fibers, to the touch uchigami paper feels like gampi paper. So to accurately determine the type of paper, it is not enough to feel it; it must be viewed with a microscope.

Identifying the material

Although all Japanese papers are made from plants each different plant gives a different type of paper. Let’s look at the different types of fibers to see where these differences come from.

First, watch the video to see Dr. Shiroto analyze a printed book from the second half of the 17th century.

Fiber analysis

Plants used to make Japanese paper belong to the Dicotyledon group. The cellulose cells in a Dicotyledon plant all look alike, so if we enlarge them we can tell with reasonable accuracy what plant they are from.

Identifying the raw material of the paper allows us to tell where the book is from. For example, Chinese books made in China and Chinese-language books made in Japan not only are bound in completely different ways but also make use of different types of paper. The paper used in Chinese books is called “bamboo paper” (chikushi). Chikushi paper fibers come from the moso bamboo, a plant of the Monocotyledon group. Unlike Dicotyledons, the cells in Monocotyledons come in a variety of shapes. Because chikushi paper could not be produced in Japan, Japan-made books in Chinese were printed on kōzogami (choshi). So as far as Chinese-language books are concerned, even if the book comes without a cover or colophon (a statement at the back of a book stating the name of the publisher, the date of publication, etc.) by examining the fibers we can tell if it was made in China or in Japan.

Correctly identifying the raw material is also of crucial importance in book restoration. For best results, the same paper as the original should be used. So one should never try to identify the paper based simply on color and consistency. What may look to the eye as gampi paper, for instance, could be kōzogami treated with the “hammering” method (uchigami) or even mitsumata paper. Only by carefully analyzing the paper using modern tools can the source material be reliably identified.

So fiber analysis is equally important for book history and book conservation.

Books examined in this step:

For your reference

Below are the data for each plant in case you get an opportunity to do formal paper analysis.

Source material Cell shape Cell size
Ramie (choma) magnified paper Flat or cylindrical with a vertical crack. The cross section is either rectangular with acute angles or elliptical. Length: 60~250㎜
Width:10~80µm
Paper mulberry (kōzo) magnified paper There are wide and narrow ones. They are ridged, have joints, and cross. The narrow ones have pointed ends, the wider ones rounded ends with an elliptical cross-section. Length: 6~21㎜
Width: 10~30µm
Gampi magnified paper Either flat or cylindrical with rifling marks; have knots, and the ends are round. Length: 3~5㎜
Width: 10~30µm
Mitsumata magnified paper Irregularly shaped with the central part twice as large as the rest; the ends are round and sometimes split. Length: 3~5㎜
Width: 10~30µm
Moso bamboo (Monocotyledon) magnified paper Large number of fibrous cells not found in dicotyledons (stem cells, tissue cells etc.) Length: 1.5~4.4㎜
Width: 6~27µm

These photos by Kazuyuki Enami, Ryukoku University.

Other helpful hints

Ramie fiber

Ramie fibers are very long and most appear to be cut. Compared to other fibers they are wider and shaped like a ribbon. Paper made from them is very white but the surface is rough.

Kōzo fibers

Kōzo fibers are longer than gampi and mitsumata fibers. They give a very white paper.

Gampi fibers

Gampi fibers have characteristically round ends. The paper tends to be less white than the preceding two fibers.

Mitsumata fibers

The distinctive characteristic of Mitsumata fibers is that the center is larger than the ends. Like the gampi, mitsumata paper is less white.

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This video is from the free online course:

The Art of Washi Paper in Japanese Rare Books

Keio University