Grain refers to the fine, three-dimensional wrinkles that appear on the surface of leather. These patterns are created through processes like hand-kneading, air-beating, and shrinking. An exception is ostrich leather, where the raised pores are considered its “grain.”

Grain size and texture vary depending on the individual hide, as well as the part of the hide used; areas like the neck, shoulders, or stomach for example, often show a wide range of fiber density and structure. Leather grain contributes significantly to a leather’s individuality, and is one of the key features that makes every bag distinct and personal.

Vein lines—faint, branch-like markings—are another unique feature found in natural leather. These are remnants of the animal’s blood vessels, most visible on the grain side, and resemble patterns like leaf veins or lightning bolts.

The more natural the leather finish, the more likely these veins are to appear. While some might see them as imperfections, vein lines are widely appreciated—especially in places like Europe and the U.S.—as proof of authenticity and a beautiful reminder of its individuality.

Unlike “uneven dyeing,” which often suggests a flaw in English, some-mura refers to the subtle, natural variations in how dye is absorbed into leather—depending on differences in fiber quality across the hide. 

It’s a concept deeply appreciated in Japanese craftsmanship, where the tonal nuances are embraced as part of the material’s inherent beauty. At Tsuchiya Kaban, we see some-mura not as an imperfection, but as a quiet, expressive depth that enhances the individuality and warmth of each piece.

As a natural material, leather often bears the physical characteristics of the animal it came from. For instance, even when large wrinkles or loose skin on the rawhide are smoothed out, the leather may still absorb dye unevenly due to differences in fiber density between the peaks and valleys of the wrinkles. This results in distinctive patterns—streaks or stripes that often resemble tiger markings, known in Japanese as tora (meaning “tiger”).

These marks commonly appear on leather made from the shoulder area, where the skin is especially elastic. Rather than being seen as flaws, these stripes are often embraced for their unique character and are intentionally featured in bags and accessories for their organic, expressive beauty.

Animals raised outdoors often carry scars from rubbing against bushes or fences, or from skirmishes with other animals. Unlike synthetic materials, genuine leather naturally bears some of these traces of life—subtle indicators of authenticity.

Hides from North and South America, where animals graze freely on open grasslands, often feature many such markings. Some may even display rare markings, like scars from cactus thorns.

Because these are scattered randomly across the hide, avoiding them entirely would severely limit usable material. As long as they don’t affect the leather’s durability or significantly impact appearance, these marks are typically incorporated into the final product in ways that minimize visibility. For designs that highlight natural character, such markings can even add a rustic, one-of-a-kind charm.

A lesser known fact about animal hides is that they naturally retain hair pores—even after the dehairing process. These traces are often minimized through treatments such as shrinking, embossing, wrinkling, or pigment dyeing. However, depending on the animal, the part of the hide, or other natural variations, some traces may remain—occasionally appearing as tiny marks known as pinholes.

In leathers like nume leather (vegetable-tanned leather), which are dyed but left largely untreated on the surface, such natural traces are often visible and celebrated as part of the material’s character. Certain hides—such as pigskin, goatskin, and ostrich—feature distinctive pore patterns across the surface, forming unique and visually appealing textures. Even in Tsuchiya Kaban’s cordovan leathers, especially those with natural finishes like water-dyed cordovan, these subtle organic features may be present and appreciated as signs of authenticity.