Clay dye processing: the colour of the earth
A story of slow fashion from Japan: mud-dyeing born from the vision of Akira Aoki, founder of GoodNeighbors Shirts
Clay dye is the colour of the earth itself. This mud-dyeing process began as the vision of designer Akira Aoki, who founded a thoughtful slow-fashion brand. One that brings together fabric treatment and modern design.
We are all born from the same earth. Precisely this connection inspired the designer to capture the natural hues of the soil in a cotton shirt. Through repeated experimentation with local clay—each season lending its own character—the brand has created shirts with a uniquely natural colour and texture.
Clay dye: a Japanese story of earth, craft, and style
Fujioka City in Gunma Prefecture, northern Kantō, is where Akira Aoki was born and raised. Surrounded by mountains and rivers, the area is blessed with high-quality clay and pure water. For centuries, it has been a major producer of earthenware, including Haji ware, Sue ware, haniwa figurines, and roof tiles.
Fujioka roof tiles, in particular, trace their origins to the founding of Ueno Kokubunji Temple—a tradition spanning more than 1,200 years.
The region’s distinctive red clay comes from the Kantō loam layer, formed by volcanic ash from Mount Akagi and Mount Haruna. Rich in iron-bearing clay minerals, its fine particles retain moisture well and offer high permeability.
Aoki’s family moved to Fujioka during the Edo period and has farmed the land for over 400 years.
Drawing on the nutrient-rich red soil and natural groundwater from these fields, Akira—who studied dyeing and weaving at Tama Art University—hand-dyes each piece himself to create his mud-dyed products.
The special quality of mud-dyeing lies in the thick, clay-like paste mixed with groundwater. Its high iron content allows clay minerals to penetrate deep into the fibres. This process swells the yarn, smooths its edges, and enhances the fabric’s softness and texture.
The finished garment carries the beautiful, uneven colouration of the clay itself—as though gently coated in earth.
These mud-dyed products are coloured using only soil and water. No chemicals. Consequently, after dyeing, the clay returns to the earth, and the water nourishes the soil once more.
Through this deeply rooted craftsmanship, the brand aims to foster new values that connect the environment, people, and society to the future.
GoodNeighbors Shirts: shirts that breathe in Tokyo
The name GoodNeighbors means “good buddy, good neighbour.” The brand values shirts that are comfortable to wear every day, and that can be shared easily and without pretence. Its original designs draw inspiration from diverse music and art cultures, each carrying a subtle, distinctive character.
Made in Tokyo, the shirts are carefully cut with a modern silhouette; skilled artisans in the city’s older districts then complete the craft. They are made to last, blending delicate tailoring with an effortless, relaxed feel—like a breath of fresh Tokyo air.
Final thoughts
Even in a market dominated by top brands and fast fashion, we remain committed to seeking out small, thoughtful gems. Ultimately, independent brands are where you will find considered design and more sustainable practices.
Clay dye processing avoids chemicals, and both the soil and the water return to nature after the dyeing process.
In a fashion system still ruled by speed and scale, mud-dyeing stands as a quiet act of resistance. In essence, Aoki’s work reminds us that colour can come from the earth, not chemicals; that craftsmanship can restore our connection to place; and that truly sustainable fashion begins with respect. For materials, for makers, and for the land itself.
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