The color of blue might be the most relaxing color in the world since it recalls the nature such as sky, ocean, river and lake by implication.

AIZOME KIMONOIn the modern world, coloring fabrics blue is often done synthetically when producing blue jeans for example, but the blue color by the Japanese indigo dyeing method called “AI-ZOME” is somewhat different.

The blue color dyed by AI-ZOME is sometimes called “Japan Blue” which has simple but deep and nostalgic atmosphere keeping unchanged popularity among people.

This time, let’s discover the charm of AI-ZOME together.



AI-ZOME is considered as one of KUSAKI-ZOME (vegetable dyeing) methods explained in the last article, using leaves of a plant called “TADE-AI” (Persicaria tinctoria, also known as Indigo Plant) which came to Japan from China around 5th – 6th century.

It came from China but presently many of western people believe AI-ZOME is from Japan.


UNGEN-SAISHIKI (in the red square)

Apparently this is because westerners visited Japan in the begining of MEIJI period extoled the blue color of Japanese garments or bedclothes and named it “Japan Blue”.
It is said they were dyed by AI-ZOME using a color shading technique called “UNGEN-SAISHIKI” (a coloring technique to give impression of gradation without shading).



Talking about the magic to create the color of Japan Blue from a plant which is green, there is a Japanese proverb which explains very well the reaction of people who saw it :

“Although (Japan) blue comes from the indigo plant, it is bluer than indigo”.

Although this is an expression for the relationship between a teacher and his student, meaning that a student can overcome his teacher from whom he has learnt, in this proverb, we can see a surprise that people long ago had over the process of AI-ZOME.

The process of AI-ZOME is very time and labor consuming.

First, to make “AI” (dyestuff of Japan blue), fermented TADEAI leaves called “SUKUMO” are placed into large pot and then by adding lye, change the SUKUMO to alkaline which is highly soluble in water. This process is called “AI-DATE” (building AI).

* Although I mentioned earlier that AI-ZOME is considered as one of KUSAKI-ZOME methods but since it is not possible to extract the blue just by boiling the plant and dye cloths directly due to its insoluble nature in water, specifically speaking, it is not usual KUSAKI-ZOME method.


AI formed in the pot

After a week in summer, 10 days in winter, the AI in the pot starts producing thick form on the surface thanks to the power of myriads of bacteria. This form is called “AI-NO-HANA” (flowers of AI)

It is said that skillful artisans can understand what the AIs in the pot need when they stir it by a “KAI” (an oar-like tool to mix things) every morning and evening to send some air.

To let the bacteria work hard and satisfy the AI, the professionals put SAKI or sugar in the pot as if pleasing a wayward young lady!

The AI in the pot in this phase looks so dirty that you might hesitate to immerse a white cloth in it, however when you put in it, and take it out to expose to air, amazingly the color changes to startling blue by oxidization.

Repeating the process of the immersion and exposure, the blue color becomes deeper and deeper by accumulating the blue in layers.

The names of the blue color by AI-ZOME are also unique, such as:


This name means “rusted and blunt blue”.
This grayish blue is realized by the process of immersing a cloth, after soaking in the AI, into dyes consisting of “TSURUBAMI” (acorns or oak nuts), “GOBAISHI” (gulls formed by infestation of aphids on the surface of sumac leaves) and “BINRŌJU” (betel palms) and then adding black color by an iron mordant.


This name means “the color of storage room”.
This dull blue with a green tint is said to show the mysterious semidarkness of storage rooms in EDO period.
Beside this, there are several types of NANDO-IRO colors such as “SABI-NANDO” (literally, a rusted storage room color), “FUJI-NANDO” (literally, a wisteria storage room color), and “KIKYŌ-NANDO” (literally, bellflower storage room color).


This name means “take a glance into a pot”.
This is the lightest blue by AI-ZOME, as the name explains, this color is dyed in a moment of taking a glance into the pot of AI.


This name means “sky color”.
As the name express, this is so-called sky blue, zenith blue or horizon, depicting the super clear blue sky.


This name means “water color”. Slightly deeper blue than KAME-NOZOKI.
In the ancient Japanese era, it was called “MIHANADA-IRO” and indispensable for summer attire together with “ASAGI-IRO” (pale blue).


As you can see, the blue colors of AI-ZOME can vary from almost transparent to very deep, so this is not just an “indigo color” while sometimes AI-ZOME is translated into “indigo dye”.

By the way, the underwear dyed by AI-ZOME has long been said to be good for bad blood circulation, rough skin, athlete’s foot and body order.

This is understandable, as the ingredients extracted from TADEAI has been used for traditional Chinese medicine long time.

I think this is because the AI is the gift from nature which means the gift from the god. ;)