official website of Oigawa Kudzu Cloth 遠州の伝統手織り 葛布を今に伝える工房 大井川葛布

How to make kudzu fabric

1. harvest

From June to August kudzu new vine grows up to 2〜3m strength. We cut off kudzu vine at the foot of it. The vine it is thick as woman's pinky , green ,has soft hair on it's surface is good for cutting. We find the vine that grows from shadow to sunlight straight.The vine which is tangled up tree or make many sub-branches is not good.We cut off leaves from root side to top . And take 5~8 of vines together then make the vines circle like a lease.

2. boil

After harvest we have to boil kudzu vine as soon as possible. If we cannot boil them soon , we put them into pail which is full of water to avoid sun drying. We need a big kettle which we can put bunch of kudzu vine into it. We pour water into the kettle by 80 percent and boil water. Put the bunch of kudzu vine into the kettle and sometimes replace the top and bottom boiling them about 20 minutes. In the way of boiling it smells like boiled green soybean and appears vivid green color. Then it changes it's color to yellow that is the best time to pick the vine out and soak them into water.

3. fermentation

Cut leaves of silver grass and lay them on the river side then put the bunch of kudzu vine on them. The top side and around kudzu vine have to be covered with leaves of silver grass . Besides cover these vines with grass seat and weight them by putting stones on that seat. After 4~5 days put hands into grasses , and find that the surface of kudzu vine become slimy and come off easily. Then take the vine out from grasses. When fermentation is good, it smells not so badly.


Wash away epidermis of fermented kudzu vine in river until black epidermis disappear completely. unwind kudzu bundle and hold hand on vine at about 30cm from bottom ,then peel bast and wash it until unnecessaries between bast and core disappear completely. If this unnecessaries still exist , kudzu thread will have low quality.
5. fukuronuki
Seize bottom of one kudzu vine and remove bast from core part. One hand keep seize kudzu vine the other hand keep on bast and pull them to reverse direction each other. In one hand bast will be left. Pinch edge of each side and pull them to reverse direction. Make figure 8 with thumb and pinky distinguishing top and bottom of vine.
6. dry
Unwind figure 8 above, flow it in river and rinse from top to bottom of vine not to hurt bast carefully.
7. wash
Dry bast on river stones. Unbend half dried bast to avoid shrink . We call this bast Kuzuo in Japanese.

8. tsuguri

Tear kzuo by 1~2cm width and tie two ends of them with weavers knot wetting both end sides with saliva. Cut off the extra parts of knot with scissors.Put this tied thread in bucket or on newspaper figuring circle. Most first thread must be coiled around hand 4~5 times enable to find it clearly. When bucket becomes full of kudzu thread , upset bucket and displace them on the other paper. Put 2~3 fistful bran on kudzu thread to avoid be entangled.Then make figure 8 with kudzu thread around a chop stick. When it becomes young cucumber size, wind thread at 3 parts and finish work. We call this Tsuguri in Japanese.


Most of all kudzu fabric are woven in plain weaving technic using silk hemp ramie cotton for warp depending on use. Weave kudzu fabric with wetted tsuguri that is in a boat shuttle. Kudzu weaving is so delicate that it can be woven just by hands.When we finish weaving,cut off extra fluff on fabric's surface. Then beat fabric with wooden comb (we call that kinutauchi) to adds fabric shine and softness.


We held workshop as above in every summer time. You can understand how to make kudzu fabric in details more if you will join this workshop. We appreciate you to join our work shop!

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Harvest time is from late May to early August. But I guess the best time is July in this region. It is naturally different depending on the climates in which kudzu vines grow . However recently I found that we can harvest up to early September if we choose kudzu vine carefully. I can distinguish good vine by just seeing them actually.

 To put bunches of kudzu vine into pile of pampas grass leaves is to promote fermentation. However it's mechanism is not clear. Oigawa kuzufu focused fermenters at the first time. There exist many bacillus subtlis on leaves of rice plant department. 37℃ same as body temperature is the best temperature for bacillus subtlis to ferment. Bacillus subtlis can decompose cellulose, so it can give kudzu fiber softness. Beautiful shinning kudzu fiber is available because bacillus subtlis never hurt fiver. When fermentation is under good condition , we find white mold that is spore of bacillus subtlis and prove fermentation process has finished

Cut off a lot of pampas grass leaves and lay them down on the ground . We recommend this method for beginner.

 We wash kudzu bast in river which has good water quality. If kudzu bast is washed with running water,it will loose it's shinning soon. We had changed the river in which we clean kudzu vines 3 times during in this 10 years to search good water quality. We realized water was polluted day by day.

In the past they soaked kudzu-o(kudzu fiber ) into washed water of rice in order to make kudzu-o whiter. But we think when kudzu-o are soaked in washed water of rice , its oiliness , shine and strength would be reduced . We think the most important matter to make whiter kudzu threads is to choose good vines.

 Drive a reed at a slant against the warp in order to avoid the kudzu thread be crushed.

 Those who work for Yaeyama jo-fu and Basho- fu make threads into cocoon-shaped tsuguri for weft. In case of using cocoon-shaped tsuguri, the weft tends to be twisted when it is pulled out from a shuttle. On the other hand, we make kudzu threads into cucumber-shaped tsuguri for weft in order to protect them against to be twisted.

The rear beam of kudzu-fu loom is usually higher than front beam , and the frame of reed is light .
This is all to protect flat kudzu thread against being crushed.