Aizome (Indigo Dyeing)
Tokushima Prefecture has a centuries-long history of indigo farming and dyeing. Locally grown indigo, known as Awa-ai, is prized for its high quality. Its production by traditional fermentation techniques, though labor-intensive and time-consuming, is still carried out today. It is said that the British chemist Robert William Atkinson (1850–1929) was impressed by the rich blue colors he saw upon visiting Japan in the 1870s. Atkinson coined the term “Japan Blue,” an expression now known worldwide, especially to fans of Japanese denim. Nearly 150 years later, the color indigo was chosen for the official emblems of the 2020 Tokyo Olympic and Paralympic Games. Visitors to Tokushima can experience a hands-on workshop in aizome indigo dyeing.
The History of Indigo in Tokushima
The indigo plant is said to have come to Awa Province (the former name for Tokushima Prefecture) in the Muromachi period (1336–1573). The farming of it developed from the Edo period (1603–1868). Cultivation spread from mountainous areas to the fields alongside the Yoshino River, which runs across the northern part of the prefecture. Frequent flooding makes this area unsuitable for rice farming, but the rich soil and abundance of water were well-suited to indigo. The first lord of Tokushima, Hachisuka Iemasa (1558–1638), promoted its cultivation and the establishment of what was to become a booming industry.
By the early Edo period (1603–1868) an increase in cotton production contributed to a nationwide demand for Awa-ai, as its pigment was used widely in dyeing. Indigo blue was one of the few bright colors that commoners were permitted to wear in the strict days of samurai rule. This helped to increase demand even more.
Indigo cultivation peaked in 1903, then dropped as cheaper synthetic substitutes were imported from overseas. The tradition of indigo production in Tokushima never completely died out, however. In recent years, interest in natural products and traditional methods of craft production have helped to raise Awa-ai’s profile once again.
The Indigo Dyeing Process
While each Awa indigo producer brings their own special techniques to pigment production and indigo dyeing, the basic procedure is similar. The leaves of the indigo plants are ground and dried, then splashed with water and allowed to ferment for about three months. This produces a pungent substance called sukumo, the base for dyeing. The pigment at this stage, however, is not yet water-soluble, and requires further processing. The sukumo is mixed with a glucose solution and sake or wheat bran, then fermented again at carefully controlled temperatures for another week or so.
Once the dye bath is ready, the cloth is dipped into it repeatedly. With each immersion, a new layer of blue depth is slowly revealed. After the cloth is thoroughly rinsed in clean water and allowed to dry, the bright color of indigo will deepen over time.
A number of workshops in the city of Tokushima offer visitors the chance to try indigo dying and produce a one-of-a-kind souvenir.
