Magazine vol.1
"Interview with the TONDO Project Managers: The Birth Story of TONDO LEATHER."
Since its release in 2020, Tondo has grown into a flagship series representing Artfear.
While the original material remains popular, the series continues to evolve through fusion with different materials such as denim and Kevlar.
Now, we have heard that development is underway for a leather model of Tondo.
From the material selection stage, numerous prototypes were made, and the new backpack belt "ZeRoG Fit" has been incorporated, resulting in a product full of dedication.
This time, to delve deeper into its appeal, we spoke with two people in charge of the project.
- The idea of making Tondo in leather has been around for a while, right?
But you hadn’t found the perfect leather until now.
That's right. During development, we considered softer leather options, including samples made from sheepskin. It was soft and leather-like, but the distinctive front shape of Tondo didn’t come out nicely.
- So maintaining a clean shape is the top priority?
Exactly. We repeatedly prototyped with various leathers aiming for that, and finally arrived at this one.
It’s domestically produced cowhide tanned by a long-established tannery in Tatsuno City, Hyogo Prefecture, using a combination tanning method with a high amount of tannin, giving it firmness yet lightness.
The surface is finished with pigment, but you can still feel the natural leather wrinkles. It’s treated with water repellency, making it more resistant to moisture than typical leather.
- The regular Tondo uses woven polyester fabric, so I assume it’s not a simple matter of just replacing it with leather?
Whenever the material changes in any product, we always review the core materials.
The usual Tondo has a thin core material only on the center back of the fabric.
At first, the leather version used the same core placement, but that caused distortion, so in the end, we used core materials in all parts.
Adding core material increases the product’s weight and can sometimes diminish the material’s qualities, so we carefully selected which core materials to use.
- You use synthetic leather on the bottom surface—is that because it’s more resistant to abrasion and friction?
Exactly.
We have data from friction tests comparing regular leather and synthetic leather. The test involves sliding the material surface under constant pressure and speed for 100, 300, and 600 cycles. Grade A is the best rating, but leather’s rating drops after 600 cycles, while synthetic leather maintains an A rating even after 600 cycles. It shows high resistance to wear.
Since this is a high-end product using leather, we want customers to use it for a long time, so we deliberately chose synthetic leather for the bottom.
- Speaking of synthetic leather, isn’t the frame wrapping on Artfear products originally made of synthetic leather?
We use synthetic leather on the frame wrapping because of its stretchability, basically.
- It stretches easily?
Yes, synthetic leather stretches easily. We want the curved parts of the frame to stretch but not the straight parts. Synthetic leather’s properties allow for both.
Can you see the curved part inside the bag when opened? If the frame wrapping doesn’t stretch, slack forms here, making the frame’s opening and closing not smooth. Also, during assembly, the distances don’t match, which causes trouble. There can be about a 1 cm difference in length between inside and outside, so if it doesn’t stretch, you have to pull it to fit.
- Is the addition of gussets to the Quattro Shoulder related to this?
The reason for adding gussets is related to the backpack we just talked about. The purpose is to make the frame’s opening and closing smoother.
With the leather, the gathered parts became slightly thicker, interfering with the frame closing smoothly. Adding gussets created space for the gathered parts to move.
See, it makes a "click" sound, right? The sample without gussets sounds different.
- Really, the sound is different?
I guess I haven’t reached that level yet... (laughs).
- I heard the backpack’s shoulder straps have evolved further this time.
Before that, let me explain the conventional "ZeRoG". It has three types of core materials with different hardness inside the belt, and these cores help the belt fit widely over the shoulder, making it feel lighter. That’s "ZeRoG".
This time, we incorporated a new material called "HUMOFIT®" from Mitsui Chemicals inside the belt. It’s a shape-memory material that changes shape with body temperature. By adding this to ZeRoG, we thought we could create a belt that fits each user’s shoulder perfectly. We really wanted to try this.
- So you insert a long HUMOFIT strip inside the ZeRoG belt?
Yes. It’s heat-bonded. HUMOFIT originally comes in sheet form. We cut it into the belt shape, then apply heat to bond it to the fabric. Maybe "heat fusion" is a better term. The exact process... wait, this part is company confidential, so I can’t go into detail.
Basically, it relates to the difference in length between inside and outside we talked about earlier.
Please understand that it’s completed by a highly advanced technique to match the distances.
We struggled through many prototypes to figure out how to make it fit the body better, but thanks to that, we think we made something satisfying.
- I tried on the sample earlier, and my shoulders are unevenly tilted, but it still fit both shoulders perfectly, which surprised me.
I definitely want people to experience this fit by actually wearing it.
Our manufacturing at Artfear starts from the concept of "creating function in form."
Bags can easily become just fashion items, but how to add functional value is always a challenge for the two planners pushing new creations.
After the interview, we heard that development of a new frame series is progressing almost simultaneously with Tondo Leather.
We look forward to sharing what kind of creatively packed bag will be born next on another occasion.