I first heard about Cozo Cazama because a Japanese professor disapproved of my German.

I was a student in Japan at the time and extremely broke. Among the various jobs I had accumulated was occasional recording work for NHK, Japan's national broadcaster. I would sit in a studio and read German words and sentences for educational programs.

There was a Japanese professor supervising the recordings who liked to correct my pronunciation. My German, he informed me, was too southern. Too Bavarian. I found this particularly funny because, as far as I could tell, he spoke neither German nor English. Nevertheless, he remained committed to improving my native language.

Somewhere between recordings, I mentioned my growing fascination with indigo. Someone at NHK told me they had recently made a documentary about a remarkable dyer in the mountains north of Tokyo. Not simply an artisan, they said, but one of those increasingly rare people who seemed to carry an entire body of old knowledge inside him.

His name was Cozo Cazama. I went to find him.

What Are We Putting Against Our Skin?

By then, textiles had become something of an obsession for me. The obsession had begun for reasons that were not particularly pleasant.

My mother was undergoing treatment for terminal cancer, and I watched her body become progressively more sensitive to the ordinary things around her. Things that had previously seemed neutral were suddenly not neutral at all.

I remember an oncologist explaining that people whose bodies are under extreme stress can become sensitive even to substances in textiles, including dyes and finishes. It was one of those observations that changes the shape of a familiar object. You look down at your shirt and think: what exactly is this?

Clothing is one of our most intimate technologies. It touches us for most of the day. We wrap newborn babies in it. We sleep inside it. We place it over wounds and irritated skin. Yet the modern textile industry generally treats the surface touching the body as an engineering problem: durability, price, consistency, wash fastness, color.

I began wondering what had been there before. Before petrochemicals. Before synthetic dyes. Before textile production became one of the largest chemical manufacturing systems on earth.

The obvious place to investigate was Japan. So I started approaching traditional dyers.

I would explain my idea, which must have sounded faintly heretical. I wanted to understand plant dyeing, but I did not ultimately want to produce artisanal scarves or one-off works of craft. I wanted to put plant dyeing into factories. I wanted machines, scale, repeatability. I wanted to know whether the layer between the human body and the outside world could once again be made from biological materials rather than mostly synthetic chemistry.

Most traditional dyers were unimpressed. For some, the use of machinery defeated the entire purpose. If human hands were removed from the process, they told me, it was no longer really the same thing. Their position was understandable. Traditional craft survives precisely because somebody, somewhere, refuses to compromise.

But I kept running into the same wall. Then I met Cozo.

The Atopy Challenge

Cozo comes from a multigenerational textile family in Ashikaga, an old textile-producing region of Japan. By the time I encountered him, he had spent decades around dyeing. His route into natural indigo had passed through the conventional textile industry, family craft, apprenticeship, and eventually a much deeper preoccupation with fermentation and traditional indigo.

But a biography does not quite explain him. Shortly after we met, he told me about what he called his atopy challenge. In Japan, atopy is commonly used when speaking about atopic dermatitis, particularly childhood eczema.

His proposition was startlingly simple. Parents of children with skin problems could bring him their clothing. He would dye it with natural indigo. The children would wear it. And, as I remember his challenge, if their skin did not improve within about a month, he would return the money.

This was not a clinical trial. Cozo did not pretend it was one. That was precisely what interested me.

He had arrived at his conviction in a much older way: observation. People tried something. They watched what happened. They remembered.

For modern science, anecdote sits near the bottom of the hierarchy of evidence, and quite rightly. Human beings are exceptionally good at seeing patterns that are not there. But virtually all science begins with somebody noticing something, and Cozo had spent much of his life noticing.

The Old Books

Inside his workshop he began pulling books from shelves. Some were very old, more than a century in age. They contained accounts of indigo and its uses that belonged to a world before anyone spoke about the skin microbiome, microbial ecology, or bioactive compounds.

Cozo showed me descriptions of how people had used indigo textiles around the body. He showed me old images of warriors wearing indigo garments and explained the traditional belief that indigo clothing had practical value in battle, including around wounds. There were similar stories about farmers and laborers.

What struck me was not whether every historical claim would survive a modern randomized controlled trial. Surely some would not. It was the underlying idea. These people did not necessarily regard dye as decoration. Color could have function. A textile could do something.

Sitting there, I realized that I had been asking the wrong question. Until then, I had thought the problem with modern textiles might be that we had introduced substances that were unnecessarily harsh, particularly for sensitive people. But perhaps there was a second loss. Perhaps we had not merely added something. Perhaps we had removed something.

For thousands of years, humans colored cloth using materials extracted from the biological world around them: leaves, bark, roots, flowers, minerals, insects, fermentation. Then synthetic chemistry arrived and, with extraordinary speed, replaced most of it.

The achievement was enormous. Synthetic dyes gave us cheap clothing, astonishing consistency, and almost unlimited color. But they also changed our definition of what a dye was for. A dye became something whose job was to make a textile a particular color. Blue was blue. Red was red. The rest became irrelevant.

Sitting in Cozo's workshop, surrounded by fermentation vats and old books, I began wondering whether earlier cultures had asked more of the materials touching their bodies.

The Traditionalist Who Said Yes to Machines

This is where Cozo surprised me most. I told him what I wanted to do. I wanted to industrialize it. I wanted to take knowledge associated with traditional plant dyeing and put it into modern machinery. I wanted to make thousands of pieces, eventually perhaps millions.

Other craftsmen had recoiled from this idea. Cozo did not. He was curious. I have thought about that difference many times since.

There are two ways to protect a tradition. One is to preserve its exact form. The other is to preserve the knowledge inside it. They are not always the same thing.

Cozo seemed instinctively to understand this. He did not need me to imitate him. He did not expect a factory to pretend to be an artisan workshop. The interesting question was whether something his tradition had learned could survive translation into another system.

That attitude became enormously important to me. It is easy to romanticize traditional craftsmen as guardians of an unchanging past. Cozo has never struck me that way. He is too curious.

Weekends With Cozo

During the week, I was still working for a medical technology company in Tokyo. On weekends, I began taking small groups out to see Cozo.

I organized experiences for visitors, usually five or ten people at a time. We would leave Tokyo and spend a day, sometimes two, learning about plant dyeing. People put their hands into vats. They dyed cloth. They watched colors change as textiles met the air.

And then there were the evenings. We would sit around a fire and talk. These journeys became an education for me, not merely in indigo but in Cozo himself, because the longer you know him, the harder he becomes to categorize.

At some point he told me that he had lived in Jamaica when he was younger. This was less surprising than it sounds. Cozo loves reggae, not in the casual way that someone owns a record, but as part of his life. He knows figures from the Japanese reggae world and has moved within that culture for years.

What interested me was what this said about Cozo. Here was a man who could devote himself to a deeply Japanese textile tradition and, apparently without experiencing any contradiction whatsoever, immerse himself in Jamaican music. He does not seem particularly interested in cultural categories. If something contains knowledge, beauty, or depth, he follows it.

Then there is his other music. Cozo has spent years working with ancient Japanese musical traditions, reaching back toward the Nara period, more than a thousand years ago. I have sat there while he and other musicians played it. It is difficult to describe because our ears have been trained by modern music to expect rhythm, repetition, a pulse, resolution. Some of this older music operates according to a different logic entirely. A note can feel closer to a vibration than to a melody.

Once I understood this part of Cozo, his indigo work made more sense to me. The ancient music and the dyeing are not really separate hobbies. They come from the same instinct. He is interested in forms of knowledge that modern people are tempted to classify as obsolete, and instead of merely venerating them, he asks what they were actually doing.

Fermentation

Natural indigo itself rewards this kind of personality. An indigo vat is not simply a bucket of blue liquid. It is alive.

Traditional indigo dyeing depends on microbial fermentation. The dyer maintains conditions in which microorganisms make the indigo chemically available to attach to the textile. The vat has temperature, smell, mood, and rhythm. You have to watch it, feed it, learn its behavior.

Modern industrial thinking prefers systems in which inputs produce predictable outputs. Fermentation is more argumentative.

Cozo has spent years studying not only the inherited practice of indigo dyeing but the microbiology behind it: why the vat behaves as it does, what the microorganisms are doing, and how traditional observation intersects with modern scientific explanation. Again, the boundary between old and new does not interest him very much. The old craftsmen knew something. Modern microbiology knows something. Why wouldn't you listen to both?

What We Forget

I am wary of writing about people like Cozo, because it is easy to turn them into symbols: the ancient master, the keeper of secrets, the last craftsman. Japan, in particular, attracts this kind of romantic projection from foreigners.

Cozo is more interesting than that. He likes reggae. He lived in Jamaica. He plays ancient Japanese music. He studies microorganisms. He dyes clothes. He reads old texts. He spends time with famous musicians and with mothers whose children have eczema. He can be deeply traditional and completely uninterested in doing things merely because that is how they have always been done.

What makes him unusual is not that he lives in the past. It is that he refuses to assume the present knows everything. That is a very different proposition.

I first went to see him because somebody at NHK told me about an extraordinary indigo dyer. I found one. But I also found a way of thinking that eventually became central to my own life. More than a decade later, I am proud to call Cozo Cazama my friend.

AIZOME today operates in an entirely different world from his workshop. We manufacture at scale. We work with scientists and factories. We think about technology, regulation, and global supply chains. But I can trace part of what we are doing back to a much quieter place: an indigo vat, some very old books, a fire in the evening, and Cozo, patiently explaining that sometimes what appears to be an obsolete tradition is simply knowledge whose explanation has not caught up with it yet.