Redcast Heritage x ONI Denim "Kerama Blue" 15oz Intense Bio-Washed Natural Indigo Jeans (2025)

Almost three years have passed since our last collaboration with ONI, and for this occasion we wanted to do something truly special. This time we wanted to create something that was really different and ground-breaking, something never seen before on the Japanese denim scene.

We have worked hand in hand with Oishi-san for two years, including a visit to Ibara, Japan, to directly collaborate with Oishi-san and the Kuroki Mills team and convey our ideas to them. After many hours of production, numerous samples, multiple fabric rolls inspections and wash trials, we are proud to present the limited “Kerama Blue” capsule.

This edition comprises 158 pairs of jeans in a new cut designed by us and 50 type-III limited-edition jackets. Each garment includes an extra-thick premium tote bag made from Kinari Hanpu cotton canvas, manufactured in Okayama and designed by Jon Kutt.

The Story Behind This Collaboration

It all started two years ago. We spoke with Oishi about the possibility of creating something different for the sunnier months. We wanted to design two garments in a capsule format —jeans and a jacket— that would generate good sensations at first glance. Our intention was to convey the essence of sun, beach and the blue of the sea. We were looking for a denim colour that would reflect all this and at the same time would stand out in a cupboard full of other denim items. You know that garment that always jumps out at you in your cupboard in spring and summer and that you can’t stop using? That’s what we wanted to achieve with this collaboration.

This team effort represents a fusion between Spain and Japan, uniting two cultures in a tribute to the wonderful blue waters that grace both countries. We wanted to capture the essence of summer and transfer it to our garments, so we looked for a blue tone that would evoke the crystal-clear waters of Spain’s Mediterranean sea and the ocean of the Okinawa islands in Japan.

The Kerama archipelago, situated southwest of Okinawa, is known for the breathtaking light blue colour of its ocean, a hue so unique that in Japan they call it “Kerama Blue”. This very special colour is deemed to be extremely difficult to replicate in both painting and in textile dyes. We set ourselves an ambitious mission: to replicate that distinctive “Kerama Blue” in a denim fabric.

Nothing in this was easy. We had to give a lot of thought to the concept, meet with Oishi and Kuroki, and talk to several washing and dyeing workshops to see how we could replicate the colour we had in mind. Doing a yarn-dyed electric blue would not have been too complicated; we could have created a fabric using indigo yarns with half the usual colour baths. But that wouldn’t have given us the colour we were after. It would have come out a nice light indigo tint but far removed from the tone of the sublime waters we wanted to achieve.

In the Ibara and Kurashiki areas of Okayama prefecture there are several washing workshops that do an incredible job with stonewash. We did many trials with stonewash but did not attain the desired result. The resulting indigo was always worn and uneven. Just like the clear waters of the Kerama archipelago, our blue had to be constant and continuous, without variations in the tone or uneven wear. The blue of our fabric had to transmit a haven of peace and calm, gloriously becalmed waters, what the Japanese call "Heion" (平穏).

We scoured many vintage shops in Koenji and Shimokitazawa on a quest for archives of 1980s and ‘90s American jeans with different treatments such as acid wash and bleach. In these jeans, the indigo, after a chemical wash and the passage of time in damp warehouses, had been left with a very light blue tone. We found some good examples and sent them to the Japanese. In several conversations between Oishi and an Ibara wash workshop, we came up with the idea of doing an intense biowash with Japanese enzymes and adding a minimal amount of bleach to obtain greater intensity without damaging the cotton. After many trials we were gradually getting closer until one day Oishi sent us an email with the subject line: 私はそれを持っている (I have it).

This is how our limited capsule was born. We were not looking for amazing fades or complex textures but for an ode to the good weather, sunshine and happiness that these colours evoke. Each piece is a tribute to the beautiful blue of the waters we enjoy in Spain and Japan when the good weather arrives, and we’re proud that we can share it with you.

The Fabric

We initially thought of doing 12-oz jeans focusing on the summer months. However, we then asked ourselves: why not use them also in the transition months or even in winter? This is why we looked for a light option that would also be resilient.

So we created a 15-oz fabric woven at very low tension to provide greater comfort, lightness and breathabilitywhile retaining sufficient weight to ensure durability and allow it to be used during the colder months.

The intense biowash treatment with a slight touch of bleach which we applied to each garment further softens the fabric, so the feeling of lightness is even greater. Despite its 15 oz, when wearing it the feel is of a 13-oz fabric.

The Details

We incorporated the characteristic ONI details such as the copper rivets and donut buttons. The patch is made from 0.5-mm horse leather in a natural, vegetable-tanned colour and was designed by the illustrator Jon Kutt. As well as the quality of the leather, there are two special aspects to the patch.

  • First, we stitched the patch on after the wash treatment. This is a regular practice in all our collaborations, although it does generate complications and additional cost because all the garments have to go back to the sewing workshop after washing. But the result is far cleaner and, because it neither shrinks nor wrinkles during washing, the beauty of the leather and the definition of the design lines are enhanced.
  • Second, we numbered each one of the units in this limited series. 158 units of jeans and 50 of jackets were produced.

The cut

We wanted to introduce a new style of cut. In our previous collaboration with ONI we chose the iconic 622, but this time we were looking to innovate with a new design. The new 240 cut represents a perfect balance between a relaxed conical cut and a straight cut. We are talking about a modern straight cut, with a medium-high rise that comfortably fits around the thigh without being too tight, presenting a slight minimal narrowing from the knee downwards. It is similar to the ONI 246 cut, though with a slightly more pronounced narrowing and a more suitable inseam length for combining with sneakers.

This cut is ideal for every taste, whether for those who prefer up-to-date straight cuts or for those who are accustomed to conical tight cuts and would like to try out the straight-cut trend.

A characteristic we love in these jeans is the notable leg twist that occurs due to the intense biowash, evoking the aesthetic of vintage jeans. As many of you know, the leg twist is due to the "right or left hand twill" weaving technique in unsanforized fabrics. This is something that is not found in sanforized fabrics or in “broken twill” weaves. In all those Japanese jeans that have a pronounced leg twist, it is not a sewing defect but a characteristic intrinsic to this kind of fabric that is impossible to find in the mass-production jeans of our days. At Redcast we love these leg twist jeans, as they are part of the history of denim. These Kerama Blue jeans combine a unique finish with a characteristic leg twist.

The Artwork and Name of the Collaboration

For this collaborationwe designed a very special pocket flasher and leather patch, perfectly reflecting the Japanese Kerama Blue concept.

We decided to associate with the talented Canadian illustrator Jon Kutt, and we are absolutely delighted with the three designs he created for us: the pocket flasher, the leather patch and the tote bag.

His designs are not only visually striking but also perfectly represent the essence and message we wanted to convey through this collaboration. The pocket flasher stands out for its bold design, which attracts maximum attention; the leather patch adds a unique touch; and the tote bag combines functionality and style in an indispensable accessory for a day at the beach.

As you can see from all we’ve told you, the process ofcreating this collaboration was time-consuming and required hours of testing to obtain the perfect result. We wanted to offer special, different, 100% Japanese-made jeans and this inevitably means that production costs were higher than usual, so we limited the number of units produced to 156 jeans and 50 jackets. However, to make it possible for these pieces to be available to the majority of our clients who would like to complete their wardrobe with a special addition, at Redcast we have made an effort to offer this collaboration at the most competitive price possible and even include a free premium tote bag with each piece. As with our previous collaborations, the goal is not to profit from this launch but to offer the possibility to denim devotees to get their hands on a pair of unique jeans or a unique jacket that have never been produced before and have a story to tell.

We truly hope that you view the Redcast x ONI “Kerama Blue” collab as a good choice of pieces in which to invest and rotate in your cupboard.

Sizing Notes

This model has standard sizing. We recommend choosing your usual size. However, as always, we recommend checking the size chart first to find your perfect fit. It is unsanforized but has been heavily washed, so there will be no shrinkage. The waist will experience the typical stretching seen in ONI denim due to the low tension weave, although not as much as the secret denim. Expect approximately 1 inch of stretching.

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

Redcast Heritage x ONI Denim "Kerama Blue" 15oz Intense Bio-Washed Natural Indigo Jeans (2025)

FAQs

Where is Oni denim from? ›

ONI, the renowned Japanese brand, takes its name from "ONI" (Devil), reflecting its distinctive "secret denim" with slubby textures. Masao Oishi, a key figure in Japanese denim, gained prominence at Levi's Japan and played a role in the first Japanese jeans brand, Canton Jeans, in the '60s.

Is Oni denim sanforized? ›

The Oni-626-LT17 is an unsanforized jeans, which means that you have to soak the jeans before you start wearing it.

What is secret denim? ›

ONI's coveted Secret Denim is the 20oz denim that earned the small Japanese label a cult following. A truly unparalleled fabric, the denim sports a unique color, intensely textured feel, and is crafted using extra thick yarn.

Why Japanese denim is so expensive? ›

The production process itself is signified by its slower production speed, and lower output. Selvage denim, at least the ones we use, relies on vintage weaving looms that date back at least 70 years. Thus, looms are scarce, and spare parts are so rare that they often need to be salvaged from other looms.

What is so good about Japanese denim? ›

Premium Materials: Worth Its Weight In Gold

Japanese denim's superior quality begins with the careful selection of materials. Renowned for using high-grade, long-staple cotton sourced from the likes of Zimbabwe or the United States, Japanese denim weaves its magic with the finest threads.

What is red cast denim? ›

Redcast denim, so named because of its slight red tint, is denim that has only been dyed with indigo. Unworn redcast denim will have an almost purplish tint to it. After the jeans have been worn for some time, the denim will fade to a clean, brilliant blue color.

What is the difference between Japanese denim and regular denim? ›

It is made on vintage looms that are 60 to 80 years old with denim production considered an artisan craft. The vintage looms create 'selvedge denim', another term used interchangeably to describe Japanese denim. The edges are wrapped in a red thread, whereas Western denim is frayed and left unfinished.

Should I wash my Japanese denim? ›

Similarly, selvedge denim can be machine washed according to the care tag, but if you want to hold on to more of that indigo we would still recommend hand washing in lukewarm water with a gentle cleaner. Whichever method you choose, be sure to rinse all the cleaner out of your jeans before hanging them up to dry.

What is heritage denim? ›

The definition of heritage denim is simple: 100 percent cotton, warp indigo dyed 3×1 or 2×1 with a left hand twill or right hand twill.

What is it called when you wear all denim? ›

by Charlie Newman. The Canadian tuxedo, aka jeans and a denim jacket or shirt, has remained a fashion statement since it was first coined in 1951.

Why are denim jeans so expensive? ›

Expensive raw materials cut into profit margins. Cotton isn't necessarily a luxury fabric but, as we covered in our guide, it comes in a variety of quality levels, and improved quality increases prices. Expensive jeans are softer, have a more natural drape, and are recognizable by their beautiful hues.

What country is denim from? ›

Denim is a sturdy cotton warp-faced textile in which the weft passes under two or more warp threads. This twill weave produces a diagonal ribbing that distinguishes it from cotton duck. Denim, as it is recognized today, was first produced in Nîmes, France.

Does Levi's use Japanese denim? ›

LEVI'S® MILLS & MAKERS

That's what we love about using Japanese denim within Levi's® Made & Crafted® – it takes the construction to an unmatched level of precision and specificity that's only attainable by artisans trained in Japanese craftsmanship.

Where does Amiri get their denim? ›

AMIRI Slash Jeans in deep classic indigo, made in Los Angeles from excellent Italian denim, almost define the brand's DNA. They are the iconic AMIRI jean, combining the finest raw materials into a cut and distressed denim that screams rock 'n' roll, music-inspired motion, and on-tour aesthetics.

Is Uniqlo denim Japanese? ›

[MADE in JAPAN with PRIDE]

This collection of premium denim represents our ongoing effort to produce jeans with higher quality fabric and an improved fit for unrivalled comfort.

Top Articles
Latest Posts
Recommended Articles
Article information

Author: Twana Towne Ret

Last Updated:

Views: 6247

Rating: 4.3 / 5 (64 voted)

Reviews: 95% of readers found this page helpful

Author information

Name: Twana Towne Ret

Birthday: 1994-03-19

Address: Apt. 990 97439 Corwin Motorway, Port Eliseoburgh, NM 99144-2618

Phone: +5958753152963

Job: National Specialist

Hobby: Kayaking, Photography, Skydiving, Embroidery, Leather crafting, Orienteering, Cooking

Introduction: My name is Twana Towne Ret, I am a famous, talented, joyous, perfect, powerful, inquisitive, lovely person who loves writing and wants to share my knowledge and understanding with you.