2. WASHI Encyclopedia

WASHI Encyclopedia:



Question 1.
What is the difference between Washi and machine-made papers?

Today, most papers we see around us are all machine- made papers (for instance, papers used for newspapers, wrapping, books, notebooks, etc.).
Machine-made papers are mass produced continuously by giant paper-machines called Four- driniers or Yankee paper- machines. Therefore, quality-wise, the papers are stable and highly qualified for mass use and con-sumption.
For instance, if the quality of printing paper called western- style paper here, is not stable, the printed matter shall not be uni-form. In order to avoid this situation, machine-made papers are standardized paper made under specified conditions from the raw material stage. The paper is made continuously by machine so there is no room for the individuality of the papermaker to show itself. But reconsidering this matter, it may be said that such machine-made papers are not “enjoyable”.
On the other hand, regarding Washi, the stages of papermaking are almost all carried out by hand. Only a certain amount of raw material is prepared and pulped at each individual papermaking plant. Therefore, although the same raw material,i. e. Kozo and Mitsumata is prepared, a small difference appears due to the indi-vidual or according to the place of growth. The papermaker uses this raw material and makes the sheets of paper one by one, so according to the papermaker, a difference shows up. and this becomes apparent as the individual characteristic of that paper.
Of course, this does not mean that the quality of the paper may be uneven but the distinguishing characteristic is that the small difference highlights the individuality of the papermaker and makes the product more attractive and compared to mass produced paper, as each paper differs, it is completed as an “enjoyable” piece of paper.
Hitherto, it was said that the Kozo fiber could not be made into a sheet by machine, but that has become possible and a paper
resembling Washi has been produced. From the consumer side, machine-made paper is ade¬quate but once Washi is handled, the soft touch and subtle warmth which cannot be explained by¬words, can be felt. It is this feeling which will touch the heart of the person echoing the warm¬heartedness of the papermaker who made the sheet of paper with devotion.

Question 2.
Why does Washi last longer than machi-made papers?

In a newspaper article dated February, 1979, it was reported that at the Congressional Library which has the largest collection of books in the U.S., 1/3 of the 18 million collection i.e. 6million books are so badly damaged that once they are loaned out, it will be impossible to repair them due to the advanced stage of deterioration of the paper used.  It is said the same situation exists in libraries in France, England and other countries.
These books are publications printed from the middle of the 19th century onward using machine –made paper (Western-style paper utilizing wood pulp as raw material which happened to become popular at that time.
On the other hand, the oldest paper made in Japan is dated the 2nd year of Taiho (702) made in the areas of Mino (Gifu), Chikuzen (Fukuoka) and Buzen (Fukuoka/ Oita) and used for census registration. The paper is still conserved at the Shoso-In Imperial Treasure Storehouse (cf. Note 1)located in Nara. There are also examples of old documents in museums which are older than 1,000 years and it is amazing to see the excellent lasting property of Washi.
The main chemical composition of vegetable matter is cellulose, hemicellulose, lignin, etc. . When making pulp, the most harmful component is lignin. The hydro-philic quality of lignin is low and if it remains in the paper it will reduce paper strength. If it contacts light or oxygen, pigmentation takes place which is the origin of discoloration which reduces the quality of the paper. For those reasons, a paper free from lignin is appropriate for preservation.
Also, in paper fibers, it is said that the higher the degree of polymerization (molecule length) and degree of crystalization, the paper lasts longer.
Wood pulp bom about the middle of the 19th century in the west, was pulverized groundwood pulp made by pressing wood against a revolving abrasive stone face so the entire lignin content remained in the paper and was the cause of deterioration. It is due to this reason that newspapers left alone turn yellowish. Later, chemical pulp production started to dissolve lignin chemically and carried out delignification treatment by blea-ching.
Vegetable fibers have a quality of absorbing water easily so if words are written in ink or printed on the paper it will run. Therefore, sizing becomes necessary to prevent running of ink. So rosin is added to the paper stock and also aluminium sulfate to maintain the pH (cf. Note 2) of the stock from 4.5 〜5.5. These elements become fixed on the fibers so the finished paper shows a weak acid reaction. Ordinarily, paper moisture content is 6 to 8 % so aluminium sulfate would cause hydrolysis and deteriorate the paper in the order of hemicellulose and cellulose which makes the paper lose elasticity. The paper becomes brittle and just by folding the paper a little, the paper cracks.
The inner bark fiber of Kozo and Mitsumata originally has little lignin and to eliminate that small amount of lignin, vegetable ash or slaked lime is used and the stock treatment is carried out under moderate conditions so the fibers are not damaged and a high polymerized (strong fiber) paper is made.
The uber of the inner bark is itself longer compared to wood fiber, so the cellulose molecule is also longer which resists acidity. Crystalization is also high and contains an adequate amount of hemicellulose which is advanta-geous to paper strength so in regard to preservation of paper, Washi ranks highly.
However, recently on the raw material side, foreign inner bark fiber pulp or strongly bleached Kozo pulp with chlorine odor has increased. Also increased mixture of wood pulp or using a large amount of chemicals during the steaming and softening stage or addition of sizing (rosin) has taken place so preservation, with the exception of Washi produced in the traditional method, cannot always be good.
Note 1.
Erected around 752 as a storage building attached to Todaiji, the temple housing the largest bronze Buddha statue in Japan. An Azekura-style structure (wooden storage building utilizing the expansion and contraction of wood to control humidity) storing treasures of Emperor Shomu (724-749) to Emperor Saga (810-823). Located in Nara.
Note 2. pH
Chemical notation of hydrogen ion con- sistancy. The pH of water at an atmospheric pressure count of 1 and Celcius count of 25 degrees is a pH count of 7. pH count above 7 is alkaline and under 7 is acid.
Answer: Akinori Ohkawa

Question 3.
What is the secret of the strength of Washi?

If chemical or artificial fibers such as rayon or nylon or animal hair are dispersed in water and scooped up in a screen and dried, they would break up into fragments and not form a sheet.
But if wood or vegetable fibers are scooped up in the same way and dried in the sun, a strong sheet is formed.
Vegetable fiber has a property of “self-adhesion” and the fibers adhere to each other at a contact point between fibers. This property was discovered accidently and became the cause of discovery and modification of paper in ancient China.
In order to understand this property of self-adhesion, it is necessary to know what fibers are.
Vegetable fiber (cellulose) is formed from glucose. The cellu-lose molecule is made up from much glucose which is connected lengthwise. This cellulose molecule does not dissolve in water but has a property to work well with water (hydrophilic) and the fiber is a large collection of cellulose molecules.
Hydrophilicness means that at some place in the cellulose molecule there are some parts which have the same type of molecule as the molecule of water and cohesion of that part and water is easily carried out. Therefore, vegetable fibers work well with water and when fibers are soaked in water, they absorb water easily and expand.
After allowing the fiber to absorb adequate water and making it into the form of a sheet and then drying it, the fibers which have cohesion with water and the part in contact with the fiber changes into cohesion between fibers and though each cohesion is weak, throughout the sheet, cohesion is carried out in so many places that it becomes a great strength and a strong sheet of paper is formed. This cohesion of fibers is called “hydrogenic cohe-sion”.
Compared to western-style papers such as newspapers, the secret of the strength of Washi is also related to fiber length. The length of Kozo fibers used in Washi measure in average 7.3 mm, Mitsumata 3.2 mm and Gampi 5.0 mm. Compared to this, wood pulp fiber length used mainly in machine-made papers are 2.3 mm in case of softwoods such as pine and fir and 1.02 mm in case of hardwoods such as beech, oak and chinquapin.

Cross section of western-style paper

Cross section of Washi {Kozo paper)

Also, from a technical point of view, the ratio of length and width of fibers (area) may be compared. The ratio is Kozo 510, Mitsumata 420,Gampi 490. Compared to this, softwood pulp fibers are 86 and hardwood pulp 60. This indicates that Washi shows a greater numerical value.
From such comparison, it can be said that Kozo, Mitsumata and Gampi are long and slender fibers but especially if a fiber is long, one fiber has many cohesion parts so even in that area only, a strong sheet of paper is formed. How¬ever, any strong sheet of paper, once immersed in water, tears easily. The reason is that which was mentioned before, water mol-ecules permeate the cohesive parts of cellulose which is hydrophilic and cohesion between fibers loosens.
Answer: Kou Amada

Question 4.
What is the secret of the beauty of Washi?

Among papers throughout the world, Washi is unique, having both natural strength andbeauty. The secret of this characteristic is that it is a manufacturing method that uses such raw materials as inner bark fibers of Kozo and Gampi, utilizes the medium of water and without any impurities forms a sheet of paper with only those fibers. This method is called “Nagashizuki” (Discharge papermaking, cf.Question #12 and Glossary).
Currently, handmade papermaking throughout the world is divided into “Nagashizuki” (Discharge papermaking) and “Tam- ezuki” (Accumulation papermaking, cf.Question #12 and Glossary). These are convenient technical terms used world-wide now but was originally Japanese craftsmen jargon which such experts as Dard Hunter (cf.Note) adopted.
During the final part of operation in handmaking of paper, ejecting water vigorously together with impurities is “Nagashizuki” and after disposing water, gently returning the remaining water backwards is called ‘Tamezuki” even today by local papermakers.
Operation of the latter method considers dressing up of the surface of the paper and the final manipulation is usually for makeup of the front surface of the sheet. (The screen surface forms the back of the sheet.)
The name of the two methods of papermaking which were only distinguished by a subtle difference of operation originally used the same mucilage and same water. But this has come to express a great contrast of methods by use of mucilage or not, difference of manipulation of water on the screen made of woven bamboo ribs or manipulation of the scooping up operation on wire mesh, etc..
So the “Tamezuki” method which was the method when papermaking was discovered in China was conveyed to the western world and if I said uNagashizu- ki” was devised in Japan, it may give you the impression that the method of manufacture after entering into Japan was totally transformed. However, it should be said that it is a wonder that tools such as the flexible screen, etc. have retained their original form over these years. Improvement of tools and raw material has been carried out more in the west.
In the beginning, in China, long fibered flax (ramie fiber about 20 cm., hemp about 2 cm) was used as raw material so such processing as cutting or grinding in a stone mortar was necessary. When using rags, etc. different sorts of raw material were mixed up. In this way, processing of raw material and a tendency to mix different material was transmitted to the west.
In Japan, fiber length is about 1 cm. so intertwining of the fiber was easy and the most appropriate material for paper, Kozo, was growing everywhere naturally. Every year, first year branches were cut from the stump and work was carried out carefully to maintain fiber quality. In this way, papermaking developed, stressing fiber strength of Kozo and Mitsumata and material selection.
For instance, there was no effort to hide traces of the screen mesh and weaving thread but as grain in woodworking is ap-preciated, this became the point of appreciating paper and the technique for production of tools necessary for weaving of screens, etc. became more refined.
The technique of processing of patterns of flying clouds or water drops in the wet sheet was also developed. The difference of the front and back surface of paper is not only due to such ostensible reasons as contact with the drying board but is due to the composition of the layer of paper and of the tempo in forming paper. Not only luster, softness and physical strength such as folding strength but preservation endurance was also thus created. This method of papermaking was completed during the great cultural movement prior to the Heian period (794- 1192) by development of national culture after assimilation of the Chinese Tang Dynasty (618-906) culture.
Dard Hunter (1883-1966); American expert on paper. Wrote many books on handmade papers, such as "Old Paper- making in China and Japan, and "Paper- making by hand in America". His books and collections are kept in the Dard Hunter Museum at the Institute of Paper Science and Technology. Atlanta, Georgia, U.S.A.
Answer: Shin Yagihashi

Tosa Tengujo papermaking

Question 5.
Why is Washi more expensive than western-style papers?

How much do often used and easily purchased notebooks or letter paper found in stationary stores or supermarkets cost?
Compared to that, Washi cannot be found outside of specialty or folkcraft shops. Price is higher than western-style papers and it seems too dear to use. However, once the paper is taken in hand, the weight of tradition and the warmth of the papermaker can be felt and when writing a letter neatly by brush on this paper, the feeling is that sincerity can be appreciated by the recipient.
The main raw materials of Washi are Kozo, Mitsumata and Gampi but let us compare the price of Washi made from the most popular Kozo and the price of western-style papers manu-factured from wood pulp.
In order to make Washi by processing the black bark of Kozo, the yield would be 30%, but in order to make 1 kilogram of Washi, 3.3 kilograms of raw material is necessary. The cost of 1 kilogram of Kozo is approximately 550 yen so the cost of raw material only would amount to 1,815 yen. Besides that, the best white bark Kozo (yield from black bark is 47%) material made from refined and processed black bark Kozo is 50% yield for papermaking so the cost becomes very expensive, amounting to 2,700 yen per kilogram. To make 1 kilo-gram of Washi costs 2,700 yen plus kilograms of raw material adds up to 5,400 yen. (costs as of August, 1989) On the other hand, western-style paper is made by a continuous process from wood-chip-pulp- paper, so the cost calculation is difficult. However, supposing market pulp is 100 yen/kilogram, the yield for paper is 90% so the raw material cost to produce 1 kilogram of western-style paper is approximately 110 yen. You can see the difference by taking the raw material cost only.
Next, let us view this from a product efficiency standpoint. As Washi utilizes long fiber Kozo as the main raw material, it is difficult to make it into paper continuously by machine but is produced by hand one by one. Generally, a day’s work (8 hrs) consists of only about 300 sheets. For instance, recalculated into the area of note-books, it only amounts to 140 notebooks (30 page pad).
On the other hand, western-style paper is produced continuously by machine, so if a 3 meter width of paper is produced at a speed of 800 meters/min. and recalculated into an area of notebooks, it would amount to about 2.06 million notebooks per day (24 hrs.) which is equal to 18,000 times of Washi production.
Taking the raw material cost, productivity and the turnover of merchandise into consideration, the cost difference between western-style paper and Washi becomes extraordinary large.
Though Washi is expensive, it continues to keep up the Japanese tradition. Amid modern industry, Washi has been living continously and is close to everybody. Take a sheet of Washi in your hand at times, feel the imbedded warmth and use it preciously.
Answer : Kenichi Miyazaki

Question 6.
What kind of raw materials are used for Washi?

Many kinds of raw materials are used for Washi and in ancient times, Asa (hemp), Kozo and Gampi fibers were used. During the Yedo period (1603-1867)Mitsumata began to be used and at present, Kozo, Mitsumata and Gampi are the representative species.
Hemp is an annual growing shrub of the mulberry family and as it grew everywhere in the fields and hills, it could be collected easily so it was the main raw material for Washi. However, as preparation of the raw material required much labor, the amount used decreased gradually. At present, it is only used for a small portion of Washi such as for Japanese painting paper (cf. Question #36).
Kozo is a low growth decidious tree of the mulberry family and at full growth the branches reach over 3 meters. Easy to cultivate and an annual crop can be obtained. The fiber is thick, long and strong so it is used for such products as Shojigami (sliding door paper, cf. Glossary), Hyoguyo- shi (mounting paper), art paper, Hoshoshi (thick calligraphy paper, cf. Glossary) etc.. As the end use is so very broad, Kozo is used most extensively as raw material. Total domestic production of Kozo was 419 tons (1980,black bark conversion) and more than half of that amount was Tosa Kozo produced in Kochi. Besides this, there are such Kozo varieties as Nasu Kozo (Tochigi), Yame Kozo (Fukuoka) and Sekishu Kozo (Shimane) which are cultivated in these various areas.
Mitsumata is a low growth decidious tree of the daphne family and the branches reach a height of over 2 meters and after planting, a crop can be obtained every 3 years.

Nasu Kozo

The fiber is soft, pliant, thin and lustrous and printability is excellent so it is delivered to the Printing Bureau, Ministry of Finance as material for Japan Bank banknotes which are known to be the finest quality banknotes in the world. Besides this, it is used for Kinshi Ginshiyo- shi (gold and silver thread paper, cf. Glossary), Hakuaishi (gold leaf interleaf paper, cf. Glossary), Japanese phonetic character calligraphy paper (cf. Question #35), art and industrial art papers but the total amount used for Washi is very small. Annual total domestic production is about 366 tons (1980, white bark conversion) and the main producing prefectures are Okayama, Kochi, Tokushima, Shimane and Ehime.
Gampi is also a low growth decidious tree of the daphne family and branches of the grown tree grow a little over 2 meters. After planting, a crop can be obtained every 3 years. The fiber is excellent raw material, thin, short and lustrous but growth is slow and cultivation difficult so wild plants growing in barren, hilly land are mainly harvested. In the past, it was used in a great amount as raw material for base paper for mimeograph paper but recently, as copy machines have become popular, the amount used for such purposes have decreased suddenly. Currently, it is used for Hakunchi- shi (paper for beating out gold and silver leaf, cf. Glossary) and Maniaishi (cf. Glossary) used for backing papers for sliding panels.
Beside these materials, according to the use of the paper, straw, mulberry, bamboo and wood pulp, etc. are used as raw materials for Washi. Also recently, such imported raw materials as Thailand Kozo, Phillipine Gampi and Manila hemp are increasing.
means paper; in a suffix form, the same character is read -garni or -shi.
means the designated use of paper, i.e. Hyoguyoshi would mean paper used for mounting.
Answer: Junji Sawamura

Kozo (Black Bark)


Mitsumata (White Bark)


Question 7.
How many days does it take to make Washi?

Though used for the same object, the number of days it takes to make paper depends upon the condition of the raw material, equipment, method of raw material preparation and the number of employees.
Let us compare the number of days it takes for a person making Seichoshi (ledger book paper, cf. Glossary) by the traditional method using 37.5 kilograms of Kozo raw material and one making Shojigami (sliding door paper) by the present processing method.

The manufacturing process of Seichoshi (white bark) is as fol-lows:

  1. Kozo (white bark) is soaked in water one night to make the bark soft. 1 day

2. Slaked lime solution is sprinkled on the Kozo material and then boiled. While boiling, the material is turned over and boiled for 3 hours. It is left in the cauldron until the next morning. 1day
3. On a fine day, the material is stirred in water to wash away the chemicals and bleached by exposure to the sun.       3 days
4. Each strand of fiber is picked up by hand and specks removed. At 3. 7 kilograms/day, it takes 10 days.
5. 1 batch consisting of 2. 6 kilograms of material is beaten for 40 minutes and beaten again by hand for 30 minutes. 2 days
6. Making 300 18 gram sheets/Board drying in Echizen (Fukui) day will take 4 days, (setting the raw material to paper yield at 55%, 1,150 sheets can be made) 4 days.
7. The sheets made the day before are pressed while making paper so no days are counted.
8. If the sheets are all brushed onto 24 drying boards, 96 sheets can be dried at once. If the weather is good, they will dry in about 1 and 1/2 hour so 600 sheets can be dried daily.  2days.
Sheet selecting, cutting and wrapping time remains but up to the drying stage, it will take 23 days provided everything is nor-mal.

Process for making Shojigami is as follows (60% cleaning of the black bark)

1.and 2. The raw material is not soaked in water but after boiling in caustic soda for 2 hours, washing is carried out. 1day
3. After washing, soaked in bleaching agent for 10-15 hours and washed again.  1day
4., 5. and 6. As the raw material is bleached, speck removal is finished in a short time so these 3 stages can be done in a day.  1 day
7. 300 18 gram sheets can be made in a day so it takes 3 days, (yield 45%, 937 sheets made.) 3 days
8. and 9. Steam drying is carried out and 900 sheets/day can be dried.1 day
Currently, Shojigami can be finished in 7 days.
For reference, reading the process stated in the Engishiki (927, cf. Note) of the Heian period (794- 1192) to make paper from approximately 2 kilograms of raw material, it took 19 days for Kozo and 32 days for hemp to make paper so it can be said that Washi was a very valuable item.

A collection of canons concerning court life, religious ceremonies, tax raising, etc.. Compilation started during the Engi era of Emperor Daigo(905), hence the name. Completed in 927. 50 volumes.
Answer: Akinori Ohkawa


Question 8.
What is the yield of paper obtained from pulp wood?

T/ozof Mitsumata and Gampi are Hthe main raw materials for Washi and there is no great difference in the yield of paper obtained from each raw material so the example of making Shojigami from Kozo is most typical.
There are many stages of process in making paper from Kozo trees but at each stage those parts not necessary to make paper are not included.
The amount of Shojigami neces-sary to cover 4 sliding latticed doors is 220 grams. To make this amount 5500 grams of Kozo trees are necessary.
The stages of process are out-lined below:
Kozo cut during winter (hiber-nating period of wood) is steamed in a wooden vessel (called Koshiki) with a diameter of 1.5 meters and
2 meters high. The bark is peeled off the steamed tree immediately and this dried bark is called the black bark {Kurokawa). In weight, this amounts to only 15% of the trees so the yield is poorest at this stage of preparation.
In the black bark state, much waste such as the outer bark, injured fibers, hibernation buds, etc. are included so it is soaked in water and softened and the waste scraped off neatly by knife and then dried. This is generally called “60% white bark”and becomes 9% of the trees. Next, the 60% white bark is boiled in an alkaline chemical and the unnecessary parts such as hemicellulose and pectin are dissolved so after boiling, it is thoroughly rinsed in water. Bleaching agent is added and rinsed again in water. This is the pulp stock and is 4.5% of the tree.
This is dispersed in water and scooped up and made into paper which in weight is 4.4% of the tree.
This paper cut into specified sizes becomes Shojigami product and is only 4% of the trees.
These are the general stages of process of making Shojigami from Kozo trees but besides this, clue to the type or use of the paper, there are cases of making paper from black bark or by further processing over 60% white bark and using more high quality white bark.
However, in either case, the amount of paper from the Kozo trees is about the same and only a small percentage of the trees becomes paper.
Answer: Junji Sawamura

Rinsing fibers in water

Kozo trees                         100% 5500 gms
Kozo trees steamed and de barked

Black bark                         15% 825 gms
Knife used to scrape off outer black bark

60% bleach                        9% 495 gms
Alkaline chemical added and after boiling, rinsed in water. Bleaching agent ,added and rinsed again.

Pulp stock                         4.5% 250 gms
↓           Paper making
Paper                                 4.4% 245 gms
↓           Cut into specified size
Shojigami product             4% 220 gms



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