The Y’2 Leather KB140T Kakishibu Type I Jacket is an extraordinary fusion of Japanese dyeing tradition and iconic American workwear, reinterpreting the WWII-era Type I jacket through one of the most time-intensive and character-rich leather processes in existence. Crafted from thick horsehide and dyed using kakishibu persimmon tannins, this jacket is designed not only to be worn, but to visibly evolve over time, developing depth, warmth, and individuality with every exposure to light and wear.

Initially appearing in a light khaki-beige tone, the jacket undergoes a dramatic transformation as the kakishibu oxidizes with sunlight. Over months and years, the color deepens into rich caramel and amber hues, much like fine wine aging naturally. This living surface makes each jacket entirely unique, shaped by the environment and habits of its wearer. Faithful to its WWII inspiration, the silhouette is short and boxy, creating a striking balance when paired with high-rise denim and heavy boots.

The leather:

This jacket is made from 1.5mm thick horsehide, chosen for its strength, grain definition, and ability to hold complex dyes. The leather is treated with kakishibu, a traditional Japanese dye made from fermented persimmon tannins that has been used for centuries in clothing, armor, and utilitarian goods.

The full tanning and dyeing process takes nearly two years to complete. Kakishibu is known for its photosensitivity—also referred to as Taiyo-zome (sun-dye)—meaning areas exposed to sunlight gradually darken and become more vibrant. Compared to standard vegetable-tanned leather, this kakishibu horsehide ages faster and more dramatically, developing a deep, glowing patina that cannot be replicated artificially.

Beyond its visual beauty, kakishibu also naturally enhances durability and resistance, making the leather tougher over time while remaining breathable and organic in feel.

Construction:

The KB140T is constructed as a faithful homage to the original WWII Type I jacket, retaining period-correct proportions and functional details. The jacket features a buttoned front, pleated chest, and a single front pocket, staying true to early workwear simplicity.

Sizes 46 and 48 feature a T-back construction, an authentic vintage detail originally used to maximize leather yield and improve shoulder mobility. Inside, the jacket is lined with cotton in the body and nylon in the sleeves for comfort and ease of wear. Every component reflects Y’2 Leather’s uncompromising standards, from stitching precision to material selection, all executed entirely in Japan.

Fit Notes: The fit follows original WWII Type I specifications: short in length, straight through the body, and slightly boxy. This cut is designed to sit at the waist and works exceptionally well with high-rise jeans. It offers a structured silhouette without taper, allowing the leather to break in naturally and mold to the wearer over time. We recommend taking your usual Japanese leather jacket size. If you are not familiar with Japanese sizing, as a reference, a size 42 fits similarly to a Western Large. As always, we strongly recommend checking our size chart and comparing it with your best-fitting jacket to ensure the ideal fit.