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Pure Blue Japan AI-019 "Aizome Natural Indigo" 17.5oz Relaxed Tapered Jeans



We're excited to introduce the most incredible and rarest jeans we've ever had at Redcast.

The cotton yarns used in this fabric have been dyed by hand with natural Indigo in Tokushima. The traditional style of Japanese indigo dyeing is known as "aizome" (藍染め). To witness it firsthand, it is easy to see that it is just as much an artform as it is a means of production. Aizome artisans take pride in their work, a fact clearly evident in every finished piece of cloth that passes through their hands.

These jeans are expensive, but the Japanese method of creating indigo dye is truly a labour and incredibly time-consuming. Leaves are carefully gathered from the indigo plant and placed under thick straw mats for months on end. In order for the leaves to properly ferment, very specific conditions must be maintained at all times. Workers must perform daily maintenance to ensure that the leaves have proper airflow and stay at a temperature around 60 degrees Fahrenheit.

From picking the leaves to completion, the entire fermentation process takes roughly one full year. Finally, after months of patience and dedicated work, the final result is something that resembles dirt, but with a pungent, vinegary aroma. This product, known as "sukumo", serves as the basis for indigo dye.

Just as the indigo-dyers of hundreds of years past, the "aizome" dyeing is a manual process, done on hands and knees while leaning over a large metal vat of inky blue indigo dye. The shade of blue after one dip will be very light, and the dipping process must be repeated many times to achieve darker colours.

The combination of this time-honoured technique and Pure Blue Japan's unique slub texture results in one of the most beautiful denim fabrics we have ever seen.

Aizome process :

1. Grow Ai (藍 in Japanese which is Natural indigo) leaves from March to July/August and cut the leaves in summer.

2. The cut leaves are fermented about for 100 days to make Natural indigo dye.

3. Hank dye the yarns by very skilled craft man in Tokushima 
Dying process : dip, squeeze and wash the bunch of yarns ← repeating this process about 12-14 times to make the dark color.

The jeans are made with all the superior-quality Pure blue Japan details such as iron buttons, high-quality pocket bags, heavy-duty bar tacks, long stitching, a custom lambskin leather patch and the signature Pure Blue Japan "shoai" embroidery (Indigofera leaf).

This pair features a Relaxed Tapered cut. It features a tapered leg from the knee down while providing ample room on the top block and thighs (PBJ 019 cut).

Pure Blue Japan is the dream of Kenichi Iwaya. Passionate about denim, he grew up in Okayama and acquired experience working in different mills around the region, until in 1997 he decided to create his own brand. Ever since, Iwaya-San has been obsessed with producing incredible fabrics with unique, slubby textures and a distinct character. This is why he only works with shuttle looms from Ibara, Okayama, using only the best cottons from the United States and India. Since its emergence until today, Pure Blue Japan has consolidated its position as one of the touchstone labels in Japanese Denim, and its excellent work has established it as one of the masters of indigo dye.

[Visit our LOOKBOOK and discover a great selection of heritage street-style outfits]

  • 17.5oz unsanforized natural indigo hand dyed Japanese selvedge denim. It is a one-wash version so expect no shrinkage
  • Hand Dyeing process in Tokushima
  • 100% cotton
  • Mid-high rise
  • Relaxed tapered
  • Heavy-duty bar tacks
  • Warp: natural indigo / Weft: white
  • Slubby and hairy texture
  • Low-tension woven
  • Selvedge line colour: blue
  • Pure Blue japan custom iron buttons
  • Hidden rivet pockets
  • Peek-a-boo selvedge coin pocket
  • Long stitching
  • Durable cotton-lined fabric in front pockets
  • Raised belt loops
  • Lambskin leather patch
  • Limited quantities
  • Made in Japan


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If for some reason you are not happy with your purchase you can return it to us within 14 days for a free size exchange or refund.

For more info please visit our returns or size exchange pages.