Pure Blue Japan | The Double Natural Indigo Sashiko Selvedge Jeans

July 13, 2021

Pure Blue Japan once again pushing the envelope of the Hank dyed Natural Indigo game. A first from the Slub Masters, this week we are stoked to announce the release of their proprietary Double Natural Indigo Selvedge Sashiko fabric.
Hank dyeing is a tedious process of hand dyeing the individual cotton threads in a rope-like fashion. The entire process is conducted and regulated by the Tokushima Japanese Indigo Artisans who have been recognized as intangible cultural treasures to the country. Natural Indigo dyeing practices date back nearly 800 years with each generation of shokunin (Japanese for Artisan) honing their craft over decades of training.
Indigo leaves are grown in Tokushima. Each batch is dried and processed for a year prior to becoming part of the Sukumo for the Natural Indigo dyeing process. Pictured above we not only see the dried indigo leaves and branches of the Indigofera plant, but also the root and soil of the plant.
All of these components are added to the indigo bath to create a thicker consistency in order to help the Natural Indigo Sukumo bind to the cotton yarns. 
The different elements help create a balanced dye which must be mixed before and after each time the yarns are Hank dyed by the shokunin, in order for the indigo to effectively penetrate the yarn.
Here we see a sample of fabric which was briefly dipped and agitated in the indigo vat to demonstrate the process of oxidation once removed. As soon as the fabric is removed from the vat you can see the intense deep green color as a result of the oxidation. However after a rinse, you are able to see the beautiful lighter hue of indigo.
Pictured above, we see the different hues of indigo which are the result of the increasing number of dips in the dye to achieve the ascending darker colors.
For the Hank-dyeing process, the shokunin will slowly dip, twirl and finally ring out the yarn bunch. This process is repeated multiple times. Following this, the yarns enter the rinse process which is conducted on custom-made machines produced for the dyeing factory. The water itself is not discarded after use but filtered and recycled to be used again for the rinse process. The shokunin will then ring out the yarns after they have been rinsed in water.
The yarns featured above have all gone through approximately 12-16 rounds of dyeing and will now be re-spun onto the wooden bobbins through the spinning process, in order to be weave-ready for the shuttle loom to produce the fabric.
Pictured above are the machines responsible for spinning the yarns.
Each yarn goes through an extremely tedious process of being manually placed by hand onto a machine which will then feed the shuttle loom to weave the fabric. 
The shuttle looms used to produce the fabric are each hand calibrated and maintained by the factory workers, with each machine capable of only producing a few meters of fabric each day.
Considering the Aizome DNA makeup of both warp and weft, the hue of indigo on the face of this Sashiko is incredibly unique.
One particular charm of PBJ's Natural Indigo fabrics is the very slow fading process. As is the case with most Natural Indigo developments by the Slub Masters, the fabric tends to retain its rich color and have an even fade aesthetic throughout the piece with years of wear. 
While the fabric itself is immensely textured, the proprietary Sashiko weave by PBJ is one of the softest we have ever come across, and is well suited for year-round wear.
Featured in the fan-favorite -019 silhouette, The Relaxed Tapered cut has a lengthier front rise, a wider thigh and aggressive taper from the knee down creating an aesthetically pleasing silhouette.

*Model is pictured wearing a Size 30. He weighs 59kg (130lbs) and is 178cm (5’10”) tall.

Size - CM Waist Front Rise Back Rise Upper Thigh Knee Leg Opening Inseam
29 76 27 35.5 28.5 18.5 15.5 86
30 78 27.5 36 29 19 16 86
31 80 28 36.5 29.5 19.5 16 86
32 82 28.5 37 30 20.5 16.5 86
33 84 29 37.5 31 21 17 86
34 86 29.5 38 32 21.5 17.5 86
35 88 30 38.5 32.5 22 18 86
36 90 30.5 39 33 22.5 18.5 86
38 96 31 40 34 23.5 19.5 86
Size - Inches Waist Front Rise Back Rise Upper Thigh Knee Leg Opening Inseam
29 29.9 10.6 14 11.2 7.3 6.1 33.9
30 30.7 10.8 14.2 11.4 7.5 6.3
31 31.5 11 14.4 11.6 7.7 6.3
32 32.3 11.2 14.6 11.8 8.1 6.5
33 33.1 11.4 14.8 12.2 8.3 6.7
34 33.9 11.6 15 12.6 8.5 6.9
35 34.6 11.8 15.2 12.8 8.7 7.1
36 35.4 12 15.4 13 8.9 7.3
38 37.8 12.2 15.7 13.4 9.3 7.7

The Pure Blue Japan Double Natural Indigo Sashiko Selvedge Jeans drop on 7/14 @ Midnight (JST)


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