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How It’s Made – Behind The Scenes At The Flat Head’s Denim Factories

Recently, I had the privilege of visiting Kojima in the Okayama prefecture, where I saw first hand how The Flat Head creates their jeans. This is an exclusive look at the manufacturing processes of their jeans. Their unique, decentralized method of production is quite different from most brands, which cut and sew their jeans in a single factory. Flat Head, however, has about half a dozen different locations in the Kojima area, each dedicated to a different stage of producing jeans.

Kojima Bridge

Kojima (now technically a part of Kurashiki City) is located in western Japan. The area is best known for the massive Great Seto Bridge connecting Japan’s main island Honshu to Shikoku. The region is a center for heavy industry as well as an important international port. More importantly for us though, Kojima is also the heart of Japan’s denim production. Many companies are headquartered here, ranging from beloved enthusiast brands to mainstream jeans that can be found in any Japanese department store.

Flat Head’s activity in Kojima is far from the typical tourist destinations.  Our journey into the heart of Flat Head’s denim production takes us far from the city’s famous factories and mills up into small, winding neighborhoods where you would never expect to see jeans being produced.

Sewing Factory Interior

First off, we visited the main office of the sewing company. They’ve been in business for over twenty-five years; a love for denim runs deep in their veins and they’ve been doing this for longer than most of our favorite brands have existed. Their workers have many years of experience that predates the manufacture of Flat Head jeans, but they’re also training the next generation of skilled workers to inherit these techniques.

They make jeans for a few other brands as well, but it’s clear that their closest relationship is with Flat Head. The CEO served as our tour guide, and he said that of the few brands they manufacture, Flat Head jeans are the most difficult to make. This office is where the company tests out machinery and techniques, cuts patterns, and works with new fabrics. This is also where samples are made. It has a variety of vintage sewing machines and tools on hand.

Our next stop took us to an ordinary neighborhood of traditional Japanese-style houses. If you didn’t know exactly where to look, you would never have known that some of Japan’s best jeans are made here. There are five or six such locations where Flat Head jeans are made, each scattered throughout Kojima.

According to the sewing company, this is a traditional Kojima way of manufacture. Compared to doing everything in a single factory, it’s slower and less efficient, particularly the extra step of transporting the jeans (in various states of completion) from one location to the next, but it allows for a depth of concentration and focus that is often unrivaled in larger factories.

Patterns and Samples

The cutting house, as the name suggests, is where the jeans are cut. The man cutting the jeans was able to tell me exactly how many layers of denim were in each stack – twenty-two. As he said, this is the optimum amount for cutting with their tools. Too many layers results in a lack of uniformity; too few, and it becomes difficult to properly control the tools.

The history of this particular cutting house goes back much farther than the sewing company or Flat Head. According to the elderly couple who lives and works here, the building is over a hundred years old. You’d be unlikely to find anything like this from other manufacturers, and getting to see the facilities and processes used inspires a deep respect for a side of Japan that has largely vanished in the twenty-first century.

Sewing Process

I also got the opportunity to cut some denim myself during this tour. I only practiced on waste scraps, but I could definitely tell that this was way harder than it looked. While most jeans are cut by automated machines, Flat Head does it all by hand. It actually reminded more of my father’s woodworking than anything I would have associated with making jeans.

Sewing Process

Next, we visited the first sewing house. Here, a single individual runs the entire sewing operation. She helms an antiquated single-needle Mitsubishi sewing machine, taking on the task of putting together the back pockets from start to finish.

Pocket Stitching

Firstly, she sews the pocket shape from a blank piece of denim, folding the edges and riveting it to the jeans. This, surprisingly, is one of the easiest parts.

She next sews the arcuates; she first uses a chalk pattern for tracing before the actual arcuate stitch is sewn by hand. Compare this to many brands, which stitch their arcuates using an automatic machine that creates the entire design at once.

After the arcs, the pocket is riveted. Once a sufficiently large stack of half-attached pockets has accumulated, she does the most difficult part of the process: stitching the pockets to the leg. This looks deceptively easy, but in fact it takes a high level of skill to make the narrow stitch of the back pockets without contacting the pocket rivets.

Our next stop was a small house at the top of a steep hill; this is the second sewing house.

Second Sewing House

My guides told me that this was arguably the most important stop of our tour; at least certainly where the most sewing takes place. The couple who run the second sewing house have a large collection of vintage sewing machines by Mitsubishi, Brother, and of course Union Special.

When we dropped in, they were hard at work on special 20 oz. collaboration jeans which are apparently a real headache to sew with all-cotton thread on vintage machines, making these are the very last 20 oz. jeans that Flat Head is going to make. Below you can see the folding of the waistband and chainstitching the bottom part, which is a slow process requiring many adjustments during sewing.


The woman below is finishing up the waistband with a single-stitch machine. This is also much slower than you’d expect, because the belt loops are sewn into the waistband as well. The conventional method is to sew the entire waistband and then attach the belt loops, but instead Flat Head jeans have the belt loops sewn in at this stage for additional strength. She also sews the leather patch with the same single stitch; it’s not attached separately.

Leather Patch Addition

As you can probably see from what we’ve toured thus far, this is not the fastest way to make jeans. However, because all of Flat Head’s jeans are sewn here (and in one other house factory with the same machinery, which was too far away for us to visit at this time), it allows for a personal touch that’s absent from mass-produced jeans as well as giving the workers greater control over processes involved. Most importantly, it lets workers completely specialize in a few select areas of expertise in a less distracting environment than a large factory.

Our last stop took us to the biggest factory since leaving the office, which had a whopping five employees working over a tatami floor. This is where Flat Head’s jeans receive their finishing touches – the hems are chainstitched here, and the belt loops are fully sewn to the jeans. This is also where hardware is attached – the copper rivets and iron buttons that age so nicely along with Flat Head’s denim.

Adding Hardware

Here we see one of the ladies furiously chainstitching a pair of our jeans on everyone’s favorite Union Special machine.

Final Chainstitching

Above you can see the belt loop attachment in progress. This machine performs the thick bar stitch that fastens the belt loops to a pair of jeans. Despite the usefulness of the machine, the belt loops still need to be properly placed by hand before being sent out.

Attaching the Belt Loops

Next we see the button hole machine. Flat Head uses a technique called ato-mesu in Japanese, which refers to the way the button holes are sewn. The conventional way that’s found on most jeans involves punching the hole, then sewing the eyelet around it. However, Flat Head’s machine sews the keyhole-shaped eyelet first, then punches the hole inside of it. The extra denim inside the eyelet actually reinforces the hole and makes it stronger. This is why you might see loose white threads around the button holes on a new pair of Flat Head jeans.

After this stage, Flat Head’s jeans and other garments travel back to the main office, where they are quality-checked and receive the final touches, like the flasher, ironing, and folding.

With the second sewing house couple, Mr. Horiuchi from Flat Head, and Chnanon from Pronto Thailand.

With the second sewing house couple, Mr. Horiuchi from Flat Head, and Chnanon from Pronto Thailand

So that’s how Flat Head jeans are made. It’s a long, arduous process but it’s worth the effort to produce some of the best jeans on the market today. Hopefully in the near future I’ll have a chance to visit some of the mills where the denim is produced as well as the shirt manufacturing facilities as well for an added insight.