JELADO Manufacturing ~Leather Products~ Vol.1 Shinki Leather, a world-renowned horse leather tannery
JELADO Manufacturing ~Leather Products~ Vol.1 Shinki Leather, a world-renowned horse leather tannery ~The quality that everyone knows. The background~
Horse leather is often spoken of with a certain romanticism in American casual wear. This time, we had the opportunity to interview Shinki Leather, one of the world's leading horse leather tanners, which produces the horse leather used in JELADO's leather jackets, and we would like to share our experience.
What is Shinki Leather?
"Shinkikaku." If you like American casual wear, you've probably heard of this company, which supplies cordovan and horsehide leather to famous domestic and international brands. What makes them so great? The answer lies in their history.
The Takagi district of Himeji City, where the company is located, has been a thriving leather industry area for about 1500 years, and since the 20th century has become famous as a producer of thinly processed horse leather used as the lining of leather shoes.
With this background, Shinki Leather was founded in 1951 as "Horse Leather Manufacturing - Nitta Shoten." From the beginning, they have been committed to a management stance that focuses on "quality," and their technological innovation and facility expansion based on maintaining and improving quality has not changed even in the 21st century.
A clear example of this is that they started full-scale cordovan manufacturing in the 1970s, which was already rare in Japan (they are currently the only company in Japan that produces cordovan from raw hides to finishing).And even now, they continue to tan horse leather with vegetable tannins "in a pit tank."
This time, we will focus on the latter, focusing on the value and reality of the vegetable tanning of horse leather in a pit, which is currently the only method of tanning in Japan.
What is tanning?
"Tanning" refers to the process of transforming "skin" into "leather." By soaking "skin" in a liquid containing tannin extracted from the bark of plants, it is possible to obtain antiseptic and heat-resistant properties, but the quality of the "leather" is determined by the manufacturing process.
There are various methods for tanning, but Shinki Leather uses two methods: vegetable tanning and chrome tanning.
Here, let us clarify the differences between vegetable tanning and chrome tanning, which are considered to be contrasting methods.
First, let's talk about vegetable tanning.
Vegetable tanning is also called "vegetable tanning" or "tannin tanning," and as the name suggests, it means that the leather is tanned using a tanning agent that uses tannins (tannins) extracted from plants.
(※The tanning method will be described later.)
By the way, Shinki Leather uses solid resin extracted from South African mimosa (the bark of the acacia tree), which is said to have a high level of tannin purity.
As you, a fan of American casual wear, know, the biggest advantages of vegetable tanned leather are that it changes over time and that it is hard and rigid. On the other hand, its disadvantages are that it is weak against water and that depending on the manufacturing method, it can be time-consuming and costly.
Next, regarding chrome tanning.
From a global perspective, it is no exaggeration to say that this is the most widespread tanning method. There are two main reasons for this.
The first is the short manufacturing time. Chrome tanning uses basic trivalent chromium as a tanning agent, which penetrates into the leather very quickly, and it is possible to tan the leather in one go in a drum (vegetable tanning can also be done in a drum; more on this later), so it has the advantage of being completed in an overwhelmingly shorter time than leather made with vegetable tanning.
Another advantage is that it is scratch-resistant and flexible. In the American casual wear industry, "aging" is seen as a positive thing, but that is not necessarily a good thing in the mass market. Chrome-tanned leather is attractive because it dyes well, requires less frequent maintenance, is soft and easy to process, and has high tear strength.
The photo below shows the leather after it has been chrome-tanned, shaved, and before it is dyed. You will notice that the vegetable-tanned leather has a distinctive brown color, whereas the chrome-tanned leather has a bluish color. This is the color that emerges after wearing a chrome-tanned leather jacket for many years.
The meaning of tanning in a pit
Now, let's go back to vegetable tanning. There are two specific methods for vegetable tanning: soaking the leather in a pit to allow the tanning agent to penetrate the leather, or placing the leather in a wooden drum to allow the tanning agent to penetrate the leather. Shinki Leather mainly uses the former method.
There's only one reason for this: it really brings out the leather's character.
(*In the case of cordovan, it is difficult for tannins to penetrate the dense fibers of cordovan in a drum, so it can only be tanned in a pit.)
So why is the pit tanning method so rare not only in Japan but also around the world?
The answer to that is also very simple.
The main reason is that this method, in which the leather is soaked in vats with low to high tannin concentrations, simply takes too much time to produce, and mass-production requires a huge investment in equipment. Furthermore, to operate that equipment effectively, deep leather shaping and skilled techniques are required.
It takes about one month for cordovan leather and about two weeks for the torso to penetrate the tannins to the inside of the leather in a pit. The result is a beautiful leather with a firmness that cannot be achieved in a drum. On the other hand, when tanning the torso in a drum, the process is completed in about two days. Considering this fact, it is somewhat understandable why many tanners around the world choose the latter method.
How leather is made
Here is a brief explanation of the process by which leather is made, which takes about 10 months.
■STEP.1 "Preparation process"
These are salted raw hides imported from Europe.
First, the horse hide is cut into the body (which will later become horsehide) and the rump (which will later become cordovan) and then washed in a drum. The interaction of alkali and lime dissolves the hair, while at the same time loosening the fibers and removing excess material.
The skin removed from the drum is put into a fleshing machine to remove any remaining pieces of meat.
*In the case of cowhide, the hide is then split to produce split leather, but in the case of horsehide, the hide is thinner than cowhide, so although it is split, no split leather is produced.
A process called pickling is then carried out in which the hides, which are in a slightly alkaline state, are soaked in a mixture of acid and salt to bring the pH level to the right level for tanning.
■STEP.2 "Tanning"
After pickling, the hides are pre-tanned, and then the underside is shaved to roughly adjust the thickness before finally being taken to the pit.
The photo below shows the bags of mimosa being put into the pits. Each tank contains a different amount of mimosa, and the skins are soaked in tanks with low tannin concentration, followed by tanks with high tannin concentration.
■STEP 3 "Drying"
In the case of cordovan, after drying for about a week, the leather is aged for a further four to five months until the tannins have permeated the entire leather.
■STEP.4 "Shaving"
After tanning, the horsehide goes through a shaving process to further adjust the thickness of the leather.
The photo below is of cordovan, but can you see at this point that the cordovan layer (top of the photo) has a different texture than the rest?
After shaving, the horsehide is lightly oiled, dried and sorted, then moved to a dark room to protect it from the sun and stored as a crust.
■STEP.5 "Dyeing"
The leather is placed in a drum with dye and oil and dyed for a day. The mixture of dye and oil, and the time the drum is turned, affect the texture and color of the finished leather. This process, which at first glance appears to be just turning the drum, requires skilled techniques.
■STEP.6 "Finishing touches"
After the dyeing process, the leather goes through a finishing process. In the case of a dye (aniline) finish, which dyes the fibers themselves, the leather's texture is brought out more vividly. In the case of a pigment (lacquer) finish, the original characteristics of the leather are somewhat diluted by spraying the pigment, but the leather is more resistant to scratches and has a vibrant color.
Another important step in the finishing process is glazing. Although the method and amount of glazing vary depending on the order, this step gives the leather surface a glossy finish and adds texture.
The photo below shows the silver surface of the leather being polished using felt.
In the case of cordovan, the unique shine is achieved by rubbing the cordovan with glass beads during the glazing process.
Also, the material may be softened by putting it in a drum and "empty beating." In that case, depending on how much it is beaten, a side effect is that it may develop a "grained" texture.
My Feelings, Then and Now
After the interview, I learned that the mechanism for making high-quality leather (although the definition varies slightly depending on the industry, the inclination, and the client) is surprisingly simple. However, at the same time, I also gained a deeper understanding of how high the time, equipment, and technical costs are to realize this simple process, and how difficult it is to achieve it.
Yoshiki Nitta, third-generation president of Shinki Leather, had this to say:
"Since our founding, we have come this far with just the desire to 'make good horse leather.' As a result, it is true that there are now more things that only we can do, but it is also true that the more we pursue horse leather, the more we see what we want to do. I'm sure we will continue to take on new challenges in the future as well."
The vision is simple, but following through is extremely difficult.
This is the very reason why JELADO is fascinated by them and uses the horse leather they make.
The first thing that surprised me when I came to the company was the large number of young people who had come from all over the country.
This interview taught me the true essence that people sympathize with and appreciate a great vision more than a great business scheme.
We hope you will look forward to the JELADO products that will be released in AW 2022, which will use horsehide made by Shinki Leather.
<Text by Kobo Tagata, Photos by Sawada Seiji>