Japanese mills (denim, fabric)
Japan's textile industry produces some of the world's highest-quality denim, fabric, and dyeing — concentrated in Okayama and Hiroshima.
Japan inherited the American textile industry post-WWII when American Cone Mills and Cotton Mills sold older shuttle looms to Japanese manufacturers as the US transitioned to faster, wider modern looms. Japan kept the older equipment running, refined the techniques, and built a craft denim industry that now sets the global quality bar.
The primary cluster is Okayama Prefecture, particularly the city of Kojima — which holds an honorary "denim capital of the world" title backed by actual production volume of Japan's top-tier denim. Surrounding mills include Kuroki, Kaihara (the largest), Nihon Menpu, Collect Mills, and Kuroki's sister mill Kuroki Wagara. Hiroshima's Kaihara is the largest denim manufacturer in Japan and supplies Levi's, Uniqlo, A.P.C., and most premium denim brands worldwide.
What defines Japanese denim quality: shuttle loom weaving (selvedge), traditional rope dyeing for indigo (vs. modern slasher dyeing), longer cotton staple lengths, and slower production with stricter quality control. The result is fabric with characteristic slubs, slight irregularities, and indigo that fades dramatically over years of wear — what enthusiasts call "honeycombs," "whiskers," and "stacks."
Not every "Japanese-mill" claim is meaningful. Some brands source basic Japanese denim and mark up dramatically; others source craft mill output and the price reflects it. Naming the specific mill is usually a signal of authenticity — Iron Heart names Kuroki, Tellason names Cone (US), Naked & Famous names Kuroki and Kaihara.
Oz (fabric weight)
Ounces per square yard — the imperial unit for fabric weight, used most often for denim, canvas, and other heavy fabrics.
Selvedge denim
Denim woven on traditional shuttle looms, producing a clean self-finished edge that doesn't fray. Slower to make, more expensive, often higher quality.
Raw denim
Denim that has not been pre-washed or pre-faded. Starts stiff, dark, and uniform; develops fade patterns specific to the wearer over months of break-in.