UNIQLO | JEANS | INVISIBLE QUALITY; Learn all the hidden qualities of our products that may not be obvious at first glance.

STRETCH SELVEDGE JEANS:

STRETCHY YET

AGE LIKE

TRADITIONAL

DENIM

Results appear
after years of wear

It's impossible to visualize how your jeans will actually age in 3 years. Stretch Selvedge Jeans are how UNIQLO satisfies the modern standard of stretchy, slim-fit jeans that age authentically. Here's how the denim is made:

STRETCH SELVEDGE SLIM FIT JEANS

STRETCH SELVEDGE JEANS: STRETCHY YET AGE LIKE TRADITIONAL DENIM

On the left is a brand-new pair of Stretch Selvedge Jeans. On the right is the same model launched in 2017 Spring/Summer(*1), which may look as though they've been vintage-processed, but have simply been worn for 3 years. The brand-new pair looks authentic with its firm structure intact, but after 3 years, the deep navy color has faded to beautiful indigo with whiskers appearing on the inner thighs and the fabric has become softer on top of its original stretch.

*1 Style number is different now but same fabric is used.

Since the debut of the first Stretch Selvedge Jeans in 2014 Fall/Winter, they've been updated multiple times until the denim used to make current products was completed for 2017 Spring/Summer. What has become one of UNIQLO's must-have basics is the result of meeting numerous, seemingly impossible demands. The concept of jeans with comfortable stretch and authentic selvedge was virtually unheard of in denim's long history. Among the many obstacles, old-style looms produced a half-century ago were not compatible with stretch yarn so for starters, they had to be remodeled. The whole project was a ground-up effort even for technologically sophisticated Kaihara, a company with a denim-manufacturing history of nearly 130 years.

Producing Stretch Selvedge Jeans that will age beautifully requires skilled craftsmanship and detailed calculation.

Kaihara

A Japanese manufacturer established in 1893 that carries out seamless production of denim - from spinning, to dyeing, to weaving, to finishing. Constantly in demand by famous brands around the world, Kaihara Denim is now a benchmark of high quality. UNIQLO's partnership with Kaihara began in 1998, and together, we develop and manufacture fabrics for various products other than Stretch Selvedge Jeans.

The denim used for our Stretch Selvedge Jeans is carefully created to keep the signature firm structure while the vertical threads fade beautifully as they age. We found the perfect balance between the desired look and feel of the fabric by using a thick slub yarn that's almost straight. In comparison, using completely straight yarn will not create the desired texture, and using yarns of different thickness will give the product a ragged feel. So by adjusting the twining and pull strengths on our spinning machine, we've succeeded in creating the perfect fabric.

We aimed for textured structure and durability with our slub yarn

The raw cotton used for warp yarn is a mixture of raw cotton bought from sustainable cotton-certified vendors. As the quality of cotton varies by climate conditions, it's important for us to secure production vendors in different regions to keep the quality stable.

If you take a look at the cross-sectioned surface of our indigo-dyed warp yarn, you will notice that only the outer circumference is dyed deep navy and the center remains white. Our craftsman says, "It not only has to retain uniformity, but the center core must be vividly white and thick as well. This white center core is key to our desired color fade, and this level of high quality is Kaihara's strength."

The color fades as the bumps on the slub yarn are rubbed from wear. As the fabric ages the white of the core is uncovered, resulting in the fabric turning a vintage-like faded blue. Our spinning and dyeing processes are carefully calculated to achieve this effect.

We dye only the outer circumference of the yarn and keep the center core pure white

The spun yarns are bundled into a thick rope and transported to a dyeing machine that's nearly 11 yards tall. It is then slid inside a pot of heated indigo dye, and as it oxidizes in midair, it turns deeper blue. The temperature, time, and speed of the process are all calculated to achieve the desired effect.

Making high-pitched clanging sounds that ring throughout the factory, the boat shuttle weaves a weft yarn into an indigo-dyed warp yarn, morphing the two yarns into a Stretch Selvedge denim fabric. The downside is that the production process is much slower - one-sixth of that of computerized looms to be specific. Even if operated 24 hours straight, it can only produce 131 yards of fabric. Since data maintenance is not fully automated either, troubles are more likely to occur and must be maintained by skilled craftsmen day and night. Operating these old-fashioned shuttle looms is not easy, and each loom differs from the others. On top of that, slight difference in temperature or humidity can alter the look of finished denim.

Although it may take a great amount of time and effort, the fabric made using the G9 has excellent elasticity, structure, surface texture, and signature warmth and durability as if it were hand-crafted. Photo above (S/S 2017 model) shows how it fades after 3 years. After 5 years and 10 years, it will further fade as shown in the photo below. Seeing how beautifully it fades, one would surely want to age one's very own pair like authentic vintage. Only Kaihara, with nearly 130 years of history, can control the weaving and dyeing process using the G9 to achieve this authentic aging effect.

A specific characteristic only an old-fashioned loom can create

What's most astonishing in the denim manufacturing process are the parts done by human hand. Whether it be the process of bundling yarn into a rope for dyeing, or the weaving process by the G9, there is no hardlined end result to aim for. It's all up to the craftsmen's sense of "feel," and should there be any deviation from it, they will fine-tune the machines accordingly. Some nuances can only be communicated as "this feel," such as roughness, firmness of structure, and thickness that cannot be expressed with words. These "feelings" that our craftsmen share as the common denominator are what keeps the quality of our Stretch Selvedge Jeans intact.

We saw that texture and aesthetics of the denim were being secured by our craftsmen's "sense of feel." Elements such as elasticity and durability, however, must be numerically scaled in order to perform thorough tests at UNIQLO's laboratory. Durability is tested twice - on the yarn before dyeing and on the woven fabric. Elasticity value is checked using an iron weight. When a brand-new finished product is washed for the first time, the fabric tends to naturally twist a certain way. To prevent this, Kaihara adds a twist in the other direction during the weaving process. This twist is also checked against pre-determined parameters. These detailed numerical conversions and uncompromising tests are the secret behind UNIQLO's high quality.

Left: Inspecting whether the twist is within parameters.
Center: Measuring strength and elasticity of spun yarn.
Right: Measuring tearing strength and expansion rate of woven fabric.

We have now seen that our denim is made by leveraging advantages of craftsmen versus machines, and analog versus advanced technology alike. Before the fabric is shipped to the sewing factory, it is inspected by a fabric inspection machine. However, the final inspections for the following criteria are all done by the human eye: checking for any "stop marks" which are the horizontal lines made if and when the loom is shut down, any traces of "fluffs" which are microscopic pieces of cotton, and for any shrinkage or damage. Our engineers catch even the tiniest fluff, which they promptly remove with tweezers if found.

Even fluffs less than 1mm in size are detected and removed.

The secret to Kaihara's precise and fully integrated denim manufacturing can be found in a secluded room behind the reception room at the company headquarters. The room dubbed the "garbage room" holds fabric samples manufactured within the last few years, which amounts to a whopping 9,500 pieces. When combined with samples held in a separate room, the total amounts to 19,000 pieces. These samples include the authentic selvedge denim, stretch denim, glitter denim, and denim with silver yarn woven in. It comes as no surprise that less than 10% of these samples have been commercialized, which is in itself a testament to the fact that successful innovative ideas are fruit of numerous trials and errors. Kaihara's history and world-leading craftsmanship, along with its never-ending desire to take on new challenges, unbound by traditions or fixed opinions, are reflected in the denim they manufacture.

1 year, 5 years, 10 years - the longer you wear our Selvedge Stretch Jeans, the more distinct its unique character becomes.

This selvedge denim co-developed with UNIQLO and launched in the past had been well-kept in a non-washed condition along with a detailed spec sheet.

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