Tone Nume: Irresistibly Soft, Uniquely Yours. –Timeless Leather Designs, Crafted in Japan

Since its birth over 20 years ago, the Tone Nume Collection has held a special place in our hearts—and our customers'—beloved for its warmth, rich grain, and companionship. Our bespoke Soft Nume leather came to be when we set out to create our "ideal" leather. Discover the untold story behind this long-loved collection.

A man in a white long-sleeved shirt and light-colored pants is leaning over a large piece of dark brown leather spread on a table. He is holding a color swatch or guide against the leather, seemingly evaluating its shade or quality. Another piece of lighter brown leather is visible underneath the dark one on the table. The floor in the background is tiled.

In Pursuit of the "Ideal" Leather

Over two decades ago, in the still-modest workshop of Tsuchiya Kaban, we set out to create a bespoke leather for a new signature collection—one with a natural yet irresistibly soft feel that customers would connect with instantly.

We also wanted a supple leather that would free our designs from the constraints of some of our other materials. Our Nume leather, for example, has a robust fiber structure and ultra-smooth finish owing to its tanning process. It's a beautiful, premium leather—but we imagined something softer, suited to gentler silhouettes.

A person wearing a white long-sleeved shirt is holding up a piece of smooth, dark brown leather, curving it slightly to inspect its quality and texture. Another larger piece of dark brown leather is draped on a light-colored surface in the foreground, suggesting a workspace or a selection of materials.

Photos of the inside of a leather tannery

An Exercise in Softness

There are several ways to soften leather. One is to increase the oil it absorbs—saturating the fibers makes them more supple. But balance is crucial: too much oil can cause the leather to stretch or fade more easily. Another method is kneading, which loosens the fibers. Milling is a common mechanical softening process, where the tanned leather is tumbled inside a large rotating drum. We commissioned our tanners to use both methods—an approach common in Western leather-producing nations but still relatively uncommon in Japan at the time.

Another method involves kneading the leather. Similar to how crumpling paper makes it softer, kneading leather loosens its fibers, resulting in a pliable and soft finish. A common technique is called “empty beating,” where the leather is placed in a large rotating drum known as a “taiko.” By vigorously striking and crumpling the leather in this drum, it becomes soft.

We commissioned tanners to employ both of these methods in finishing the leather. Applying generous amounts of oil and subjecting it to “empty beating.” While such treated leather was common in leather-producing nations in the West, it was relatively uncommon in Japan at the time.

The New Face of Tsuchiya Kaban: Leather Designed to Be Touched

Through meticulous trial and error—adjusting tanning methods, oil quantities, and drum rotation speed—we finally achieved the softness we'd imagined.

Infused with around three times the usual amount of oil, the finished leather keeps a certain robustness while offering a softness that feels instantly familiar. Feeling that smooth, tender touch for the first time, our designers knew they had broken ground on a new kind of material.

Tone Nume Medium Shoulder Bag. Crafted carefully by Japanese artisan

Tone Nume Medium Backpack. Crafted carefully by Japanese artisan

Beyond its soft, supple feel, our Soft Nume leather has other distinctive qualities. Abundantly infused with oil, it develops a deep, antique-like allure without sacrificing durability. The balanced scent of leather and oil adds another sensory layer to the material. And the process highlights the leather's natural grain, giving it depth and expression—letting the character of each hide show through, so every piece is one-of-a-kind.

Through patient experimentation, we arrived at the leather we'd set out to make—one that celebrates the natural texture and grain of the hide, with a luxurious, invitingly soft touch. Uncommon in Japan at the time, this soft, tannin-tanned leather became the foundation of a decades-long bestselling collection—its gentle silhouettes and distinctive grain now synonymous with Tsuchiya Kaban.