How Japanese Denim is Made in Okayama

Why the World Is Drawn to Okayama Denim

Okayama Has Everything Needed to Make Denim

Okayama is home to both the Ibara area, known for indigo dyeing since the Edo period, and the Kojima area, which developed through the production of heavy student uniforms from the Taisho to Showa eras. Cotton was also cultivated in these regions.

So when jeans arrived in Japan after the war and the idea of making domestic denim began to take shape, it was only natural that attention turned to Okayama.

A Uniqueness Refined Against the Global Current

For Americans, jeans were originally workwear and everyday clothing, valued for being inexpensive and mass-produced.

In Japan, however, the pursuit went beyond replication or quality improvement. By tracing denim back to its roots, a new value was found in “vintage” — a way of thinking almost opposite to the American approach.

As a result, techniques such as distressing and indigo dyeing for rich fading developed further, and Okayama came to be recognized around the world as a place where ideal denim can be made.

Okayama Denim Rooted in Tradition

The main processes of denim production are spinning, dyeing, weaving, and sewing. Among them, indigo rope dyeing — rooted in Okayama’s traditional indigo expertise — is one of the defining techniques of the Ibara area.

The beautiful aging known as “fading” is made possible by a highly developed dyeing technique called shinpaku, which leaves the core of the yarn white while dyeing only the outer surface.

Okayama is also home to weaving mills that still operate vintage shuttle looms once used for classic denim, meaning the region holds every element required to make denim.

Rope Dyeing Sought After by Designers Worldwide

As mentioned earlier, the Ibara area has long been active in indigo dyeing, and the technique known as shinpaku is especially highly regarded. Because it determines the quality of fading in vintage denim, designers around the world continue to seek it out.

Let’s take a look at the rope dyeing process.

Warping

“Kei” in seikei refers to warp yarns. To ensure smooth and even dyeing, each yarn is carefully stretched through space, checked for twists or debris, then bundled by the hundreds and wound onto a cylinder.

Dyeing

The yarn wound during warping is bundled into rope form and dyed with indigo. By dyeing only the outer layer while leaving the core white, the yarn is able to produce denim’s characteristic beautiful fading.

Unlike standard dyeing processes that use high temperatures for quick depth of color, indigo dyeing is done at room temperature. That means the yarn must be dyed repeatedly, with each cycle exposed to air to oxidize into indigo blue.

It is this time and labor that creates Okayama’s distinctive Japanese indigo blue.

Selvedge Woven on Vintage Looms

Vintage shuttle looms are known for creating selvedge edges that prevent fraying on both sides of the fabric. All of the looms still in operation today are old, and many are kept running by repairing them with salvaged parts from broken machines.

One Pair of Selvedge for Every Four Standard Pairs?

Fabric woven on vintage looms is known as selvedge denim. To make it, warp tension is kept as low as possible, and the fabric is woven slowly and carefully — a method that demands time and highly skilled hands. The loom width is about half that of a modern loom, and daily output is also only about half.

In simple terms, that means for every four pairs of regular denim jeans, only one pair of selvedge jeans can be produced. Yet this inefficiency is exactly what creates the unique fading and character that make selvedge denim so valued around the world.

Kojima, Where Denim Sewing Experts Gather

Because Kojima has a long history of sewing school uniforms and military garments, it developed the equipment and technical foundation needed for denim construction. Its factories are able to handle thick denim with precision, meeting the demands of designers who care deeply about stitch work and finishing details.

WASEW’s “THE DENIM” Series

“THE DENIM” is WASEW’s original Made in Okayama denim, developed over seven years by designer Hironori Kanan. Created through the process introduced in this article, it is selvedge denim made by a true denim enthusiast, with careful attention paid to every detail.