Studio Visit: BUAISOU, Brooklyn

How the Japanese artisans create natural indigo dye from scratch

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Here at CH, indigo is our muse (we’ve even dedicated a Gift Guide to it this year) but sometimes, the final product can’t tell the entire story on its own. Natural indigo blue is not an easy color to achieve, is the takeaway from our conversation with BUAISOU, a unique collective that not only grows and harvests indigo leaves in Tokushima, Japan but also does the actual dyeing—merging two distinct crafts. From farm to fabric, it’s a long-term, attentive process likened to making wine—and requires hands in every step of the way—at the end of which emerges a vivid spectrum of shades. The blue’s boldness pierces the soul, and so does the vision of these artisans. This week, we visited BUAISOU’s small but airy first-floor studio where co-founder Kenta Watanabe shared how their vat of fermenting sukumo dye comes to life in Brooklyn.

Watanabe is, in fact, a former “salaryman” (the Japanese nickname for someone who works in an office) who changed gears after taking an indigo dyeing workshop in Japan. It’s the reason why BUAISOU hosts weekly introductory workshops—which took place in director (and helpful translator) Sayaka Toyama’s Bushwick living room until they moved into a studio space earlier this April. There’s no better way to appreciate the living beauty of indigo than by plunging your arms deep into the dark abyss.

But first things first: BUAISOU’s indigo comes from their Tokushima farm, where the plants are harvested in the summertime. The leaves are separated from the stems, then dried. Over autumn and winter, the leaves are gathered into the nedoko, or “bedroom,” where they will compost for a few months. The BUAISOU team pours water and turns the gigantic pile once a week for even decomposition and, as the weather turns cold, covers the pile with straw mats to keep the fermentation process going. Come spring, this concentrated indigo in the form of “sukumo” is ready to become liquid dye.

Watanabe and co-founder Kakuo Kaji apprenticed under sixth-generation sukumo master Osamu Nii, whose much larger farm is only five minutes away from BUAISOU’s, and who was featured in Catherine Legrand’s stunning book “Indigo.” Nii, for example, advised exactly how much water to add and how they should stir the piles—there’s much more skill involved than what meets the eye. He still frequently walks over to check how their nedoko is doing; class is never concluded.

Watanabe notes how few sukumo masters are left in Japan. After cheaper synthetic indigo was developed and became more popular, what used to total in the thousands has dwindled down to a number countable on both hands. One difference between Nii and BUAISOU, he points out, is that their teacher only farms and makes the composted sukumo, which he sells to dyers. BUAISOU, wanting to keep everything in-house from start to finish, aspires to master two separate crafts: sukumo-making and indigo-dyeing.

Dried indigo leaves smell of tea—and it’s drinkable. The clumps of fermented sukumo, in contrast, have an earthy scent, like soil. There are only four ingredients: wheat bran (a sugar to feed the bacteria), limestone powder (aka calcium hydroxide), a blend of wood ash and hot water (a highly alkalized lye), and the sukumo. Mix it all together in a vat, and after 10 days of stirring at a consistent temperature of 72-72°F, the living (and continuously fermenting) batch is ready to impart luminous blues. It will last around two months before it’s time to make another.

What differs between dyers is the ratios of each ingredient used. Also, many dyers use sake in lieu of wheat bran, but the latter is actually an older recipe—created during a time when sake was quite precious.

Sinking his arms into the vat, Watanabe soaks a square cotton fabric in the indigo dye. A few minutes later, he pulls it out—and it’s green. But the color quickly oxidizes to blue right before our eyes. Traditionally, the Japanese have identified 48 different shades of natural indigo and have given each its own name. Every year, the sukumo harvest will vary in which group of shades turns out most “beautiful,” whether it’s the lighter, middle or darker blues. A garment might be re-dipped up to 30-50 times to reach the darkest blue. “When a vat is young, it is very strong,” says Watanabe. The palest shades of indigo, which require just one or two dips, can only be achieved right before a vat “dies.”

“I get excited about the surprise,” says Watanabe of the dyeing process. “A lot of people ask is, can you make this color. But that’s not our point. Every single piece will be a different color and you should enjoy it, rather than having the same thing.”

“It’s our goal to make jeans, 100% dyed in sukumo,” says Watanabe, noting that they might be the first brand to do so. They hope to begin production next year and are happy with taking their time. Thus explains the name, BUAISOU, which refers to the name of a country house owned by Jiro Shirasu—one of the first Japanese public figures to be photographed wearing American jeans. “With regular jeans, each yarn is not completely dyed; only the surface of the yarn is dyed. Sukumo uniquely can dye to the core. So how it fades is completely different from regular jeans,” says Watanabe, giving the example of how boro fades.

Despite how challenging it is to make each batch of dye, this precious sukumo was created to be shared. In addition to teaching traditional techniques like shibori, katazome (stencil-dyeing) or Japanese batik, BUAISOU offers appointments where you can bring your own garments to be dyed. Breathe new life into your white shirts sporting a stain or two, even tired old bedsheets. Unlike synthetic indigo, natural indigo can not only strengthen fabric but also (incredibly) doesn’t bleed or transfer—so you can toss it in the laundry with whites. (Dyed pieces can sometimes yellow over time in the sun due to the remnants of scum, but a wash in hot water will help remove it.) BUAISOU’s enthusiasm for upcycling and re-adding value makes us appreciate their work even more.

There are a few different ways NYC residents can get hands-on with BUAISOU, especially before the end of the year. Every Tuesday at 7PM, they host two-hour Introduction to Sukumo Indigo-Dyeing class. This Saturday, 19 December, there’s a special furoshiki-making session at Atelier Courbet from 12-6PM (inquire by email to shop[at] And finally, they’re holding open studio hours from 12-6PM on 18, 20, 21-23 of December; walk-ins are warmly welcome to join their holiday card-making sessions. BUAISOU’s studio is located at 117 Grattan St #101, Brooklyn, NY 11237.

For those outside of the city, BUAISOU just launched their webshop, where they’ll be adding dyed pieces on a regular basis. They are often collaborations with other Japanese artisans.

Tokushima indigo farm images courtesy of BUAISOU; slideshow images by Josh Rubin; images of Brooklyn studio by Nara Shin