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Denim Glossary

Aizome (Indigo dye)

Aizome is the Japanese word for indigo dye. The first part of the word, Ai (藍) represents the color indigo, and Zome (染め) is the common term for dye.


Chainstitching is a type of inter-looping stitch which resembles the pattern of a chain. A technique originally developed by the ancient Chinese, chainstitching is embraced by premium denim manufacturers in their craft. Notable for the desired roping effect it yields over time, it is used on the hem of the leg opening of premium jeans for the durability factor as well as to avoid fraying.



Crotch Blowout

Often caused by the friction of riding a motorcycle or bike (amongst other activities), with repeated agitation to the crotch area, the fabric can wither and eventually tear when a large opening will form as the yarns unravel. This is commonly referred to as a Crotch Blowout.


Natural indigo dye

Natural indigo dye is derived from the leaves of the indigo plant. The plant's leaves are dried and left for composting in the initial stage, which takes approximately one hundred days. This yields the dense dye compost the Japanese call sukumo. The sukumo is then added to a vat of warm water which already contains a mix of several ingredients including lime, and in some cases even sake.  Once the contents of the vat has fermented, the remaining foam may be used as a natural indigo dye.

Natural indigo dye has been a part of the Japanese textile culture for centuries. It came into particular prevalence during the Edo period because it was the best type of dye for use on cotton fiber at the time. It is sometimes referred to as ''Blue Gold' amongst enthusiasts.



This French city is most notable for it's textile production, including Serge. 'Serge de Nîmes' (in english means Serge of Nîmes) is from where we derive the word denim.

Okayama Denim

Many Japanese manufacturers of denim agree that the water in Okayama has a high mineral content coupled with favorable pH levels. This combination helps to produce high quality denim fabric, which also assists in the depth of color and resilience of the indigo dye.

Another factor would be the prevalence of factories using vintage shuttle looms to produce their denim fabric.  Although the production of denim on shuttle looms yield much less fabric (about 40m a day) than the mass production of projectile looms, the quality of the selvedge fabric which the shuttle looms output is far superior than the modern projectile looms. 

Japanese attention to detail during the production process is unrivaled. The brands we carry at Okayama Denim have very small scales of production, ensuring that each product is developed with tedious attention to detail.

The use of indigo dye is not new to textile production in Japan. Traditionally, Kimono fabric was also sometimes indigo dyed, and thus the technique of rope dyeing has been a part of textile production in Japan for centuries. 

Ounce (Oz.) denim weight

When referring to the denim weight of a pair of jeans, the measurement is made according to the amount of cotton that was used to produce one yard of denim fabric. So a 17oz. raw denim means that 17 ounces of cotton warp and wefts yarns were used to produce just one yard of that denim fabric.


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Raw denim

 Raw or Dry denim refers to denim fabric which has not undergone  any treatment or coloring after the dyeing stage of production. As  opposed to washed denim which features styled fading at the time  of purchase, Raw denim is typically a dark indigo blue as a new  product. The areas that a pair of jeans will show the most wear and  fading include the ankles, behind the knees, and upper thighs. Often  considered the most desirable aspect of Raw denim is the fact that  the fade patterns and patina which develop over time, and will be  unique to the body type of the user and his/her daily activities. Raw  Denim will shrink approximately 1-2 inches around the waist after  washing. While this will not affect the actual intensity of fade  contrast, in order to perfect the natural whiskers and honeycombs, the  best way is to wear the same pair of jeans everyday for at least three to six months before washing.


A rivet is a permanent metal fastner that is used as a reinforcement on the pocket corners of jeans. Originally patented by Russian-born tailor, Jacob Davis, with the financial support and backing of Levi Strauss and Company in 1873, rivets are found on almost all jeans today.

Rope Dyeing

The rope dyeing technique which is common in Okayama, creates a beautiful yarn. It is the physically enduring process of dyeing the cotton threads in indigo and then twisting the yarns together to mimic a rope. Leaving the core of the yarns undyed, it is the understood guarantee that the finished denim garment will fade perfectly with age and time.

Sanforized / Unsanforized Denim

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Selvedge denim

Selvedge (or selvage) denim is produced on vintage shuttle looms, the way that denim was originally made for work wear before it became a global fashion statement. The fabric which is derived from a shuttle loom will have a clean, self-finished edge which will not fray or unravel. 

It is more durable and of superior quality when compared to the output of any modern day projectile loom. This is because more time and effort is put into each meter of denim produced on a shuttle loom, the way garments used to be made before mass production blinded manufacturers. The lateral weave used to complete the selvege line comes in a variety of colors.

Selvedge denim has become the fabric of choice for premium jean producers around the world. A turned-up cuff reveals the clean, finished edges as two colored stripes running up the seam of the jeans. These stripes were most commonly red in color, but today can be found in a range of colors and variations. In the early days of Japanese jeans, the stripe was used as an ID tag that distinguished the different denim fabric manufacturers in Okayama.


Serge is a type of cotton twill created by a two-stitch upward and downward pattern, resulting in a rough and rugged textile. Serge, known for it's durability and longevity as a fabric, has been used in many countries for industrial workwear, and military uniforms  Denim is a derivation of this fabric.

Shuttle Loom

Vintage shuttle looms produce a denim fabric, which among purists is considered to be of the best quality. The technique of fabric construction on a shuttle loom is very different, and on a much smaller scale, compared to the industrial projectile looms. Selvedge denim fabric produced on shuttle looms are of superior quality and will last a lifetime. 


A Twill weave can be identified by its ribbing. The combination of a weft yarn running through the warp yarn creates a Twill. Denim most commonly comes in right hand twill, although left hand twill is also available in smaller amounts as only a number of seweing machines create left hand twill fabric. Even less common is broken twill denim which features a zig-zag pattern weave, similar to Herringbone.


The set of yarns held in tension which run lenghtwise on a loom, are called warps. When looking at finished denim fabric, the warp end is the thread which runs along the fabric (parallel to the selvege line).  The warp thread is normally tougher than the weft thread as it is held in high tension


Weft is the thread/yarn which runs widthwise (from edge to edge) to hold the warp thread together. The weft yarn moves across the selvege denim from edge to edge, through the warp yarn loops. The reason Selvage does not fray is because the weft threads are looped over and under the warp.


The fading pattern appearing on the front top block of the jeans after months of wear.

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