Blue Japan – how indigo 藍 (ai) dyed Edo and became the color of work, purity, and harmony
The color of the shogunate era
In the Edo period, Japan was blue. Not metaphorically – quite literally, the country was awash in shades of indigo — 藍 (ai). One only has to look at ukiyo-e: Hiroshige, Hokusai, Kunisada, Yoshitoshi — they painted a world saturated with this color. Fabrics hung out to dry above the streets, noren curtains before teahouses and sentō bathhouses, light yukata patterned with white waves, delicate tenugui hand towels and furoshiki wrapping cloths — blue covered bodies, homes, and streets. It was the color of work, of everyday life, of aesthetics.
For the people of Edo, it was something natural, almost invisible, like the air. For foreigners arriving in the 19th century, it was a revelation. British chemist Robert William Atkinson, who visited Japan in 1874, wrote:
"This country is blue. The roofs, the clothes, the curtains — everything is blue."
And so the notion of “Japan blue” was born — a term the West coined for something that, to the Japanese, was simply life. For 藍 (ai) was not merely a color — it was a living process. It came from the leaves of the Polygonum tinctorium plant, which, after harvest, were fermented into sukumo — a dense mass in which billions of microorganisms “birthed” the dye. Indigo masters, 藍師 (aishi), fed the sukumo with ash, sake, and bran, carefully maintaining the temperature and humidity. Fabrics were dipped repeatedly, and only contact with air revealed the deep blue hidden within.
The rigorous ken’yakurei sumptuary laws of the Tokugawa shogunate made 藍 (ai) the color of Edo. Bright colors and silks were reserved for the elite; peasants, craftsmen, and merchants wore simple, practical fabrics. Indigo was ideal: cheap, durable, antibacterial, and protective against both sun and insects. 藍 (ai) became the color of labor — the noragi work jackets of farmers, the yukata of townsfolk, the belts of fishermen — and of purity: noren curtains before sentō bathhouses, blue picnic sheets for hanami, tenugui hand towels, and rice sacks.
藍 (ai) permeated daily life, yet in Japanese aesthetics it symbolized purification, breath, and harmony between humans and nature. Today, when we look at Hokusai’s or Hiroshige’s ukiyo-e, we see not only landscapes of Edo but a pulsing blue — one of the purest symbols of Japanese aesthetics. Let us now look more closely at this color, its kanji, and how it helped shape the aesthetic of the Edo period.
The kanji 藍 and the meaning of blue: “ai”
The character 藍 (ai, on’yomi “ラン”) belongs to the class of “semantic-phonetic” characters. Its meaning is carried by the upper radical 艹 (grass/plant), which directly signals the botanical world: 藍 originally refers to the dye plant itself and only secondarily to the name of the dye and the “deep blue” derived from it. The phonetic element is related to the character 監, from which the Sino-Japanese pronunciation ran is derived. In other words: 艹 tells us “this is a plant,” while the 監 component suggests “how it was pronounced” in the ancient phonetic system, from which Japanese preserved the reading “ラン” (ran).
Within the phonetic component 監 lies a subtler historical layer of meaning. Ancient forms of this character depict a vessel or “bowl” (皿) and a “watching eye,” which gave it the sense “to observe, supervise, look deeply.” While not a literal etymology of the dyeing process, it carries a strikingly apt artisanal association: 藍 (aizome — indigo dyeing) is precisely about constant watching — checking the vat, measuring its temperature and alkalinity, feeding the solution with ash and bran, tending to the “health” of the fermenting sukumo. A character born from the combination “plant + (phonetic) looking into a vessel” resonates beautifully with the lived experience of indigo dyeing — though this connection is interpretative rather than graphically original.
In the Shuowen Jiezi — the oldest great etymological dictionary of Chinese writing — we find this concise entry:
「藍，染青草也。从艸，監聲」
(“藍: the grass used for dyeing blue; composed of the grass radical, with the phonetic 監.”)
This shows that the original meaning of the character encompassed both the dye plant and the practice of blue dyeing, rather than an abstract concept of “blue” itself.
From the continent, the character’s story travels to the archipelago. In classical China, 藍 (Lán in Chinese) referred to the plants used to produce dye (various species of indigo) and, by extension, to the blue color derived from them. In Japan, the character was adopted with the reading あい (ai), coming to name the plant itself (Polygonum tinctorium), the dye obtained from it, and the entire craft: 藍染（あいぞめ）— aizome, literally “dyeing with ai.” During the Edo period, dozens of technical and artisanal compounds arose around this practice.
The philosophy of ai is beautifully captured in a famous proverb from classical tradition (quoted here in its Japanese form, not Chinese):
青は藍より出でて藍より青し
— from the “Quanxue” (勸學) chapter of Xunzi (3rd century BCE):
"Blue comes from indigo, yet it is bluer than indigo itself."
Its meaning can be read in two ways. First, the master–disciple dynamic: through practice and discipline, the student can surpass the master — the very foundation of Edo’s artisanal pedagogy. Second, nature–culture: the raw plant is the beginning, but the culture of work (fermentation, vat rules, oxidation cycles) draws from nature an intensity that nature itself “does not reveal” without human intervention. This thought captures aizome perfectly: the leaf holds the promise of dye, yet only through living fermentation — nurtured by human hands — is the deep blue 藍 (ai) born.
To see precisely what 藍 names, it’s worth distinguishing it from 青（あお, ao）. 青 (ao) is one of the oldest, “primordial” colors in Japanese, traditionally covering a range from blue to green (hence 青葉 “green leaves” and 青信号 “green light” at traffic signals). Ao is a broad perceptual category — the “cool side of the spectrum.” 藍 (ai), on the other hand, refers to a specific, saturated blue — the product of plant and fermentation. In dyeing practice, its shades are defined by the number of dips and the “strength” of the vat: from pale asagi through deep navy kon, to the historically prized 勝色 (kachi-iro — “the color of victory”) at the highest saturation. 藍, then, is not about “sky and sea” (those belong to the broad realm of 青 ao), but about earth, leaf, and vat — a color that is made.
This making is both chemical and metaphorical. In the living vat of aizome, the dye is reduced to a colorless, soluble form (“white indigo”), which allows it to penetrate deeply into fibers. Once removed from the vat, it oxidizes — the fabric, which moments before looked greenish, darkens into blue in open air. 藍 (ai), then, is not about static “states of being,” but about states of process.
From the perspective of language and writing, it is striking that the character unites 艹 (plant life) with a phonetic whose ancient imagery evokes a vessel and “looking into it”: plant + vat + eye/attentiveness — biology + craft + mindfulness. This triad of meanings resonates profoundly with the Japanese idea of learning through repetition, with the rhythm of the hands, and with the quiet ethics of work.
Tokushima and “Awa-ai” – the birthplace of Japanese indigo
South of Kyoto, on the island of Shikoku, lies Tokushima — a land whose history has for centuries carried the scent of earth, moisture, and the fermenting leaves of the indigo plant. It was here, in the broad valley of the Yoshino-gawa River, that the art of aizome (藍染) — the traditional dyeing of fabrics in the deep, vibrant blue of ai (藍) — was born. During the Edo period, this color spread across Japan, from the humble noragi work garments of farmers to the most refined silk kimono.
Tokushima’s climate seems almost designed by nature specifically for this plant. In summer, the humid heat spurs rapid growth; in winter, the earth rests, and the crystal-clear waters of the Yoshino-gawa irrigate the fertile fields. This environment created perfect conditions for cultivating indigo plants — so perfect, in fact, that as early as the Kamakura period (12th–14th centuries), this region became the beating heart of Japanese textile dyeing. Over time, Tokushima developed its own style, its own craft, and its own legend.
Thus “Awa-ai” (阿波藍) was born — the indigo of the former Awa Province, whose quality quickly became renowned across the country. In the 16th century, local authorities placed special protections over its cultivation and processing, recognizing its immense economic value. Over time, the “Awa-ai” brand became synonymous with the purest, deepest blue — a color worn in Edo by both peasants and samurai. To this day, workshops in Tokushima preserve this tradition, one of which is led by Kenta Watanabe, a contemporary master aishi (藍師, “indigo master”).
Kenta is a dyer of the old school. He personally sows the seeds of the indigo plant each March, tends to their growth throughout the summer, harvests the leaves, and transforms them into sukumo (蒅) — the fermenting mass that forms the very heart of Japanese indigo. Sukumo is a living being. For three months, the stacked leaves breathe, heating up from within, changing structure, nourishing and awakening microorganisms. Only from this material is the dye vat created. The pigment itself is the work of a microscopic universe — of bacteria, enzymes, and time. From the moment the seeds are planted to the first immersion of fabric, nearly a year passes.
Tokushima is also famed for its wealth of dyeing techniques, which, during the Edo period, allowed aizome masters to create an endless variety of patterns:
♦ Danzome (段染め) — subtle tonal gradations achieved by immersing the fabric gradually, producing delicate transitions of blue.
♦ Shiborizome (絞染め) — Japanese “tie-dye”; the fabric was tied, twisted, and bound to create asymmetrical, fantastical patterns of white and blue.
♦ Itajimeshibori (板締絞り) — a variation of shibori; the cloth was folded and clamped between wooden boards, resulting in geometric designs reminiscent of origami.
♦ Bassen (抜染) — after uniform dyeing in indigo, patterns were created by applying bleaching agents, producing intricate ornamental motifs.
♦ Roketsuzome (蝋結染め) — the most demanding technique, in which wax was carefully applied to the fabric before dyeing, creating delicate, hand-painted illustrations.
Each of these methods was, in the Edo period, not merely a craft but also an everyday aesthetic. In a world where luxury was restricted by ken’yakurei (倹約令) — sumptuary laws that forbade commoners from wearing silk or vivid, expensive dyes — indigo became the color of universal elegance. It was used to dye noragi — the work kimono of farmers, tenugui — thin cotton hand towels, and noren — shop curtains swaying gently in the streets of Edo.
Indigo in everyday Edo — the color of work and purity
If one were to capture the image of Edo in a single color, it would undoubtedly be the deep, vibrant blue of indigo. In the 17th and 18th centuries, the city could have been called a true “city of blue” — from bustling shopping streets to the bay, from temples to riverbanks, shades of 藍 (ai) spread everywhere. This happened not only because of aesthetics but above all because of practicality, economy, and law.
The Edo period was a world governed by ken’yakurei (倹約令) — sumptuary laws regulating the appearance of residents according to their social class. The Tokugawa authorities sought to maintain strict hierarchy and forbade the lower classes from wearing luxurious fabrics or vivid, costly dyes. Purples, scarlets, gold, and even certain shades of green — all these were reserved for the aristocracy and high-ranking samurai. Peasants, merchants, craftsmen, and fishermen were expected to dress modestly, in subdued, natural, “pure” tones.
And it was precisely here that indigo — 藍 (ai) — became salvation.
Edo in shades of 藍 (ai)
Imagine, for a moment, a summer street in Nihonbashi. The air trembles with heat as crowds flow between the market stalls. Merchants lean over bolts of fabric, bargaining over the price of yukata — light cotton kimono dyed in indigo. Craftsmen stand at the thresholds of their workshops, dressed in short happi jackets — working coats emblazoned with bleached white crests against deep blue backgrounds. Noren curtains, hung over shop entrances, sway gently in the breeze — always blue or blue-and-white, symbolizing purity and inviting customers inside.
On the rooftops, dozens of tenugui — thin cotton towels — are drying, often decorated with simple geometric patterns: stripes, waves, checkerboards. Most are in shades of blue and white. On their travels, Edo’s townspeople use furoshiki — square pieces of indigo-dyed fabric used to wrap clothes, food, and gifts. In the streets, one sees zabuton — blue floor cushions, blue “picnic” cloths spread beneath blooming cherry trees for hanami, and even rice sacks stacked high in the market — all woven from cotton dyed in 藍 (ai).
Blue was literally everywhere. One only has to look at ukiyo-e from the period — Hiroshige, Hokusai, Kunisada, Yoshitoshi — to see scenes of Edo life steeped in blue. For Europeans visiting Japan in the 19th century, this was a shock. Robert William Atkinson, the British chemist who arrived in Japan in 1874, is said to have remarked:
"This country is blue. The roofs, the kimono, the curtains — everything is blue."
It was at this moment that Japanese indigo gained its now-famous name: “Japan Blue.”
The color of work
In the Edo period, indigo was first and foremost the color of work. Anyone who rose at dawn and returned late in the evening, exhausted, wore the color 藍 (ai).
Peasants put on simple noragi (野良着) — loose, short kimono made of patched cotton. They wore them for years, and when the fabric began to fray, it was reinforced with additional layers — thus were born the famous boro (襤褸), patchwork garments that today are icons of wabi-sabi aesthetics.
Fishermen chose sturdier fabrics dyed in deep 藍 (ai), resistant to saltwater and sun, and protective against insects. Craftsmen — carpenters, blacksmiths, potters — wore hanten (半纏) and momohiki (股引き), work trousers dyed with indigo that not only concealed stains but also stayed fresh thanks to the antibacterial properties of the 藍 (ai) dye.
Hikyaku couriers (飛脚), sprinting through Edo’s streets with parcels, wore light jackets in the color 藍 (ai), adorned with white emblems of their guilds (more about couriers in Edo here: The Shogunate’s Reliable Couriers – Hikyaku and the Carrier Market of Medieval Japan). Even construction workers used indigo-dyed materials, because their resistance to sweat, sun, and bacteria was invaluable.
Samurai and indigo 藍 (ai)
Although 藍 (ai) became the color of peasants and craftsmen, samurai wore it as well — albeit differently. Beneath their richly decorated yoroi armor were layers of shitagi (下着) — undergarments, shirts, and hakama, often dyed with 藍 (ai). This was not a matter of fashion but of practicality: indigo had antibacterial effects, protected small wounds from infection, repelled insects, and kept the fabric fresh.
Among samurai, the shade 勝色 (kachi-iro) — “the color of victory” — was particularly prized: a deep, almost black blue obtained by repeatedly immersing the fabric in the 藍 vat. It was worn in battle as a talisman of good fortune.
Aesthetics and emotion — “Japan blue” in art
There is something deeply moving in the way indigo blue — the color of work, purity, and everyday life — also became the color of longing. In the Edo period, 藍 (ai) infiltrated not only the lives of city dwellers but also art, aesthetics, and feeling, becoming one of the most important symbols of Japan’s visual identity. Thanks to it, Edo is remembered not only as a metropolis of trade and craft, but also as a land of blue landscapes, blue curtains, and a quietude hidden in the contrasts of white and indigo.
Ukiyo-e and the blue revolution
At the beginning of the 19th century, Japan experienced what art historians call a “blue revolution.” In the 1820s, Prussian blue — known in Japan as bero-ai (ベロ藍), the pigment invented in Europe and also known as Berlin blue — reached Edo. It was more intense, deeper, and more durable than the dyes previously derived from plants, and at the same time cheaper.
As a result, ukiyo-e — woodblock prints that had until then employed a rather subdued palette — suddenly blossomed with new shades of sky and sea. Hokusai used bero-ai in his famous series “Thirty-Six Views of Mount Fuji.” The deep waves of “The Great Wave off Kanagawa” would not be so dramatic were it not for the contrast between the almost navy blue of the sea and the snowy white of the foam. The same holds for his “Red Fuji” and views of rivers — thanks to the new pigment, the water became lively, dynamic, almost three-dimensional.
Hiroshige, master of landscape and mood, experimented even more boldly with bero-ai. In his series “One Hundred Famous Views of Edo", the blue of skies, rivers, and distant hills creates a profound sense of melancholy. In the print “Kanda Kon’ya-chō,” we see the dyers’ quarter, where whole streets are draped with fabrics dyed in 藍 (ai). Blue sheets of cloth dry in the wind, forming an almost abstract landscape — the city merges with the blue, and the blue with the city. The impression is very powerful…
Sometsuke — Edo’s blue ceramics
A similar story unfolded in the world of craft. In the Edo period, sometsuke (染付) ceramics — white vessels decorated with cobalt and shades of blue — became immensely popular. Porcelain from Arita and Imari spread throughout the country. On delicate bowls and cups, artists painted waves, clouds, birds, and plum branches; the blue motifs symbolized purity and tranquility.
Sometsuke was not reserved for the elite — this porcelain appeared in townspeople’s homes, on merchants’ tables, in teahouses and inns. It was an everyday blue, yet far from banal: calming, bringing harmony to interiors and ceremonies.
“Japan blue” through foreign eyes
For the inhabitants of Edo, 藍 (ai) was self-evident, but for foreigners arriving in Japan in the 19th century, it was a true revelation. Robert William Atkinson, the British chemist who in 1874 studied Japanese dyes, popularized the term “Japan blue,” which quickly entered the European lexicon.
Even more ardently about Japan’s blue wrote Lafcadio Hearn (Koizumi Yakumo, more about him here: Japanese spirits took him in – the wandering of Lafcadio Hearn, author of Kwaidan) — a writer and lover of Japanese culture. In his memoirs, Japan appears as a country where blue permeated every fragment of daily life: from roof tiles and noren curtains to yukata and towels in sentō. Hearn wrote of a “sea of blue” that stirred his senses and evoked purity and the simplicity of life.
The greatest strength of 藍 (ai) aesthetics, according to Hearn, reveals itself in simple juxtapositions of blue and white. In the Edo period, this duo dominated not only clothing and ceramics but also decorative textiles, curtains, bedding, towels, and even toys. Yet it was not a purely decorative choice — blue and white brought a sense of freshness, order, and cleanliness.
Yukata in blue-and-white waves, noren adorned with stylized kanji, the geometric kasuri patterns on kimono, porcelain with motifs of pine and crane — all this created a coherent aesthetic language that united practicality with the poetry of everyday life.
We find the same aesthetic language in ukiyo-e: there, blue meets the white of snow, the white of sea foam, the white of plums and cherries. Japan in the Edo period was a world in which a simple, natural palette of colors allowed artists to tell stories filled with deep emotion.
Metaphysics or pragmatics?
Blue in Japan is a paradoxical color. It grows from the earth, from the leaves of the indigo plant, from fermentation, from the damp scent of sukumo, and at the same time it became an almost metaphysical realm — a symbol of purity, peace, and contemplation. In Shintō tradition, blue was associated with water, air, and purification — spheres that bind the human world to the world of kami. In zen aesthetics, where silence becomes the answer to an excess of words, blue was like a pause in which stability is found.
But 藍 (ai) is not only a symbol. It is a color of hands. The color of hands plunged into the vat, the color of bodies bent over the workbench, of days and nights measured by successive immersions of cloth. In the Edo period, indigo became the color of life in nature’s rhythm: leaves planted in March, harvested in summer, fermented for months, until at last they came alive in water and fibers. Ai was not a ready-made pigment — it had to be cultivated, fed, kept alive.
This philosophy is also embodied in the idea of boro — textiles patched, stitched, and repaired across generations. Boro is not only fabric, but a story of modesty and survival, of a world in which nothing is disposable. It is a philosophy of living in harmony with nature and the rhythm of things — allowing them to live longer, to gather history, to soak up layer upon layer. Every patched noragi, every fragment of futon, became a testament to the bond between human and matter, to the rhythm of hands and the breath of time.
And yet blue did not remain solely in the past. Today it lives on — though in different forms. You can see it in the suits of salarymen, in school uniforms, in the materials of minimalist Midori and Traveler’s Company notebooks. It is the same color once worn by peasants, craftsmen, and merchants — the color of work, simplicity, and everyday dignity — and at the same time a color that has become synonymous with modern Japanese design, harmony, and discipline.
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"Strong Japanese Women"
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未開 ソビエライ
An enthusiast of Asian culture with a deep appreciation for the diverse philosophies of the world. By education, a psychologist and philologist specializing in Korean studies. At heart, a programmer (primarily for Android) and a passionate technology enthusiast, as well as a practitioner of Zen and mono no aware. In moments of tranquility, adheres to a disciplined lifestyle, firmly believing that perseverance, continuous personal growth, and dedication to one's passions are the wisest paths in life. Author of the book "Strong Women of Japan" (>>see more)
Personal motto:
"The most powerful force in the universe is compound interest." - Albert Einstein (probably)
Mike Soray
(aka Michał Sobieraj)
未開 ソビエライ
An enthusiast of Asian culture with a deep appreciation for the diverse philosophies of the world. By education, a psychologist and philologist specializing in Korean studies. At heart, a programmer (primarily for Android) and a passionate technology enthusiast, as well as a practitioner of Zen and mono no aware. In moments of tranquility, adheres to a disciplined lifestyle, firmly believing that perseverance, continuous personal growth, and dedication to one's passions are the wisest paths in life. Author of the book "Strong Women of Japan" (>>see more)
Personal motto:
"The most powerful force in the universe is compound interest." - Albert Einstein (probably)
Mike Soray
(aka Michał Sobieraj)
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