Indigo – Aizome

Indigo was probably introduced to Japan from southern China sometime soon after the fifth century.The oldest evidence of indigo dyeing in Japan dates back to the 10th century. In Japanese, indigo dyeing is known as ai-zome. The plants can grow about two and a half feet high. Their stems are green or almost red, and their large leaves are green, but turn dark blue when dried.

In the early 1900’s Japan grew almost 40,000 acres of indigo. Today it has no more than six commercial producers, harvesting about 70 acres. Most of the farmers are in Tokushima on Shikoku, the smallest of this country’s four main islands. In indigo’s heyday, this fertile region was considered wealthy. Indigo was so valuable that 18th-century farmers who shared their production secrets with outsiders were supposedly beheaded.

Indigo fields are seeded in March and harvested and dried from July to September. In early October the dried leaves are ”put to sleep” for the winter. This is when composting begins, using a system in practice since the 10th century. Composting takes place in a building called a nedoko, or sleeping bed with a floor made of absorbent clay. Dried leaves are spread on the floor, moistened with water and formed into rectangular piles about three feet high. Once a week the piles are turned. They are carefully sliced through, turned upside down and reshaped. Each pile contains four to six tons of dried leaves. The turning process requires six hours and four workers.

During winter the piles are covered with rice-straw mats to retain the heat generated by fermentation. To encourage a successful batch of sukumo, an indigo master will place an offering of saké and a decorative bough of pine on each pile and pray to Aizen Shin, Buddhist guardian deity. The piles are composted for three and a half months before being shipped to dyers.

To learn more about Indigo, go to

Aizen Kobo 

This workshop lies a few blocks from the world-renowned Nishijin Textile and Weaving district. This indigo dye workshop and retail shop produces a wonderful range of hand-dyed indigo clothing items using techniques such as shibori (tie dyeing) sashiko hand stitched embroidery, ikat and double ikat (resist dyeing and weaving). The shop also offers products made with other natural dyes including madder.

Ai no Yakata

A dyeing studio specializing in indigo dyeing. You can participate in their class on dyeing T-shirts with indigo.
Address: 276 Onagase-cho, Ohara, Sakyo-ku, Kyoto City
Business Hours :10:00a.m.-5:00p.m. Closed every Tuesday
Reservations Required
Closed : Year-end and New Year Holidays
Access: Kyoto Bus to “Uenomiya”.

The deep blue of indigo dyes is one of the best known natural colors in the world. Indeed, it is the blue which has made blue jeans so popular the world over. Natural indigo dyeing is one of the oldest dyeing methods in the world.

One type of indigo dyeing is considered to be over 4,000 years old. Extensive evidence shows that indigo was widely used in ancient Egypt and India. The Chinese character for “ai (= indigo)” has been found in records dating back to the 1st century AD. Indigo blue or ai-iro in Japanese, long praised for its deep, rich color, dates back to the 10th century.

There are many different kinds of traditional indigo dye processes. The unique Japanese method yields a color that is known as ”Japan Blue.” Kyoto is home to a few indigo craftsmen who continue to keep the Japan Blue dye tradition alive. This month, KVG introduces you to this ancient world of color and textile wonders…

The history of indigo dyeing in Japan
The word “indigo” originally refers to a dye from India. Indigo can be obtained from a variety of plants including indigofera, storobilanthes and polygonum. In Japan polygonum or tade, is used in the natural indigo dye process. The oldest evidence of indigo dyeing in Japan dates back to the 10th century. In Japanese, indigo dyeing is known as ai-zome.

The first ai-zome textiles came to Japan from Southeast Asia. A number of indigo textiles can be found in the 8th century treasure trove in Nara’s Shoso-in Repository (part of Todai-ji Temple). Japanese ai-zome dyeing has its roots in the Heian period (794-1185). By the Kamakura period (1192-1333) the Japanese method was well established.

Japanese ai-zome culture exploded in the Edo period (1600-1868) when laws were passed preventing the lower classes from wearing silk and cotton became the popular alternative. In addition to being readily available (the indigo plant is native to Japan), ai-zome was also color fast on cotton and thus faded slowly, adding to its appeal.

Though the polygonum or tade plant grows all over Japan, Shikoku Island has long been the main production area in Japan. The Awa region (present-day Tokushima prefecture), with its rich soil and abundant water supply, was especially suited to indigo plant farming. About 200 years ago, the Awa region was one of the wealthiest areas in Japan, due largely to indigo production. It continues to be Japan’s dominant area for indigo leaf production.

Materials used to prepare the dye
There are five basic materials used in Japanese indigo dyeing: sukumo (the tade leaves of the Japanese indigo plant), fusuma (wheat bran), sake, hardwood ash, and lime.

Ai-zome dyeing is a very complicated and long process. The chemical compound indican contained in the raw leaves is converted into indigo by fermenting the leaves. The traditional process uses only natural materials and no chemicals of any kind.

Sake and fusuma facilitate the fermentation process. Wood ash (ash lye or aku) and lime are used to control the alkaline levels of the dye stuff. Wood ash for indigo dyeing is a very delicate material and must be stored carefully or it loses its power. Lime is usually added three times directly to the vat.

All these materials are mixed in a large vat (about 540 litres) and moderately heated (between 20-25 degrees C). The entire mixture is fermented for about one week. The vat is buried in the ground to more easily keep the temperature stable.

The fermentation process completely determines the quality of the final dye produced. In the ideal fermentation process a sponge-like foam (called ai-no-hana or indigo flowers) forms at the top of the vat.

Dyeing the textiles
When the fermented indigo solution is ready the cloth is repeatedly soaked in the vat. If the textile is long, for example an obi sash or roll of kimono cloth, the craftsman slowly and carefully pushes it bit by bit towards the bottom of the vat. The textile is left in the vat for 15-30 min., depending on the depth of color desired and then removed.

After squeezing the excess liquid from the textile it is spread wide and hung on a rope. This allows the textile to oxidize and thus fix the color. Just after the textile is removed from the vat it looks dark green. As it oxidizes it turns blue.

The soaking and oxidizing steps are repeated over and over until the final desired color has been produced. For the darkest blues soaking lasts 30 minutes and is repeated 30 to 40 times.

Varieties of Indigo Blue

Shira Ai (White indigo) 
Kame Nozoki (Looking into the vase) 
Usu Ai (Light indigo) 
Ruri Kon (Lapis lazuli blue) 
Tetsu Kon (Iron blue) 
Nasu Kon (Eggplant purple) 

Interview with Toru Shimomura of Ai no Yakata
Natural ai-zome craftsman in Ohara village

Discover the beauty of indigo dyeing
Toru Shimomura is an indigo dyeing craftsman. His studio is in Ohara, a rural area about 30 minutes northeast of Kyoto City. For a craftsman, Shimomura is still young but his passion for indigo dyeing is pure and intense.

Shimomura was born in Nishijin, a district of Kyoto famous for its brocaded textiles, especially obi sashes. His parents managed a shop selling a variety of indigo dyed goods. However, as is often the case in traditional craft industries, the number of experienced elder craftsmen decreased and good quality indigo items became harder and harder to find. At the same time, many craftsmen began to make use of chemical dyes. As a result, his parents almost decided to close the business but Shimomura decided he would continue.

”Though I have helped out in my parent’s business since I was a university student, I never thought I would take it over let alone become an indigo dyer myself. Actually, when I was young I wasn’t even that attracted to indigo blues. I thought they were boring and dull. While I helping my father, I began to understand and appreciate the depth and beauty of indigo blues,” Shimomura recalls.

Once he decided to take over the business, he went to a master of natural plant dyeing in Yamagata Prefecture and studied indigo dyeing with him for about two years.

Life as a craftsman
Everything Shimomura learned from the dye master was new and in the process he became increasingly attracted to the world of indigo dyeing. Finally in May of 1993, he opened a dye studio with his father in Ohara and named it Ai no Yakata, The House of Indigo. He chose Ohara because of its abundance of clean water, essential for dyeing.

”Natural dyed indigo has a certain depth of color and reflects light in a way that is very different from textiles made with chemical indigo dyes. I was also fascinated with the rich range of blues that could be produced with natural indigo, a range not possible with chemical dyes,” Shimomura says.

”Sadly, most ai-zome products sold in Japan today are chemically dyed. It can’t be helped considering the decreasing number of trained traditional craftsmen and the reduced availability of good quality natural raw materials [peak annual production of sukumo was hundreds of times higher than it is today]. However, the more challenging the situation became the more I wanted to show people how beautiful and special natural ai-zome and Japan Blue are.”

Indigo is alive
Shimomura confirms that the most difficult and important process in natural indigo dyeing is the preparation of the fermented indigo mixture. ”Indigo is alive, like human beings. A new born baby is full of energy while an old person has less energy but is full of depth and experience. Indigo is exactly the same – a newly fermented indigo solution has strong energy but it can only be used for about 2 weeks and then it is finished. Even the color produced by a vat at the beginning and end of the day are different. Like people, indigo gets tired after working a whole day,” Shimomura explains smiling.

Following his passion and devotion to ai-zome, he works in his studio as well as showing off his products around Japan. His hands are permanently dyed and at first glance it appears that he is wearing gloves. ”Since ancient times, Japanese people have said that an indigo craftsman can’t do something bad because the color of his hands immediately identifies him!”

Kobo Ai no Yakata
In Ohara: take Kyoto Bus #17 or #18 from Kyoto Station or Keihan Sanjo Station; Tel: 075-744-2404; Open: 10:00-16:30; ; open by appointment only (call in advance; Japanese only).

Aizen Kobo
Ai-zome in Nishijin

The Aizen Kobo workshop lies a few blocks from the world-renowned Nishijin traditional weaving and textile district. This indigo dye workshop and retail shop produces a wonderful range of hand-dyed indigo clothing items using techniques such as shibori (tie dyeing), sashiko embroidery (hand stitching), ikat and double ikat (resist dyeing and weaving). The shop also offers products made with other natural dyes including red madder.

This family business, now in its third generation, started out as an obi sash weaving studio. The second-generation head of the family added indigo dyed textile production and for a while ran both businesses side by side. At a certain point it became clear that the kimono industry was rapidly shrinking and the family decided to concentrate on the indigo business only and sold all their obi weaving looms.

The present head of the business, Kenichi Utsuki (3rd generation) has been invited to many universities around the world to lecture on natural indigo dyeing. His wife, Hisako, is the designer of many of the clothing items they sell in their shop.

Aizen Kobo produces their indigo dyed textiles in the traditional way. They use the same basic ingredients: indigo plant leaves, wheat husk powder, limestone powder, lye ash, and sake. Their dye vats are in operation year-round and are kept at the right temperature with heaters placed directly in the vats. To ensure quality Mr. Utsuki even taste tests the sake before adding it to the vat.

Aizen Kobo’s indigo process produces an incredibly vibrant, deep blue color that hardly fades over time. Some of their blues are so intense and deep that they appear to be black. They have pieces in their collection that are 50-60 years old and they look quite new. For comparison the studio has chemically produced indigo textiles from several countries that they show to customers to educate them on the unique color depth of naturally dyed indigo textiles