Most mills comb neps out of their yarn. Pure Blue Japan leaves them in, and for its Double Nep denim it uses nep yarn in both the warp and the weft rather than the usual one. Neps are the small knots and flecks of short cotton fiber that show up as pale specks and bumps on the surface, and doubling them gives this 16oz selvedge denim a dry, rough, uneven hand closer to homespun cloth than to conventional denim. The DNP-005-IDSM puts that fabric on the brand's slim straight cut.

Color does the rest. The warp is rope-dyed indigo; the weft is dyed with sumi, the ink of Japanese calligraphy, made from natural soot bound with glue and ground with water before it is applied to the yarn. Where a white weft would make the indigo read bright, the sumi weft pulls it deeper — a smoky, subdued blue-black with no glare. Pure Blue Japan keeps the details in the same key: the deerskin leather patch, the embroidered leaf emblem on the back pocket and even the sewing thread are tone-matched to the fabric, so nothing interrupts the surface.

Wear will bring the blue forward at the knees, seat and seams, but with a sumi-dyed weft underneath, the fades never go to white: they keep the smoky cast of the fabric, while the neps wear first and push the texture further forward. At 16oz the denim starts stiff and takes its time, which is the point of a fabric like this.

The 005 is Pure Blue Japan's slim straight, a standard cut that has stayed in the range across eras: a mid rise — 10.2" at the front on a size 32, just below the natural waist — slightly slim through the seat and thigh, then close to straight from the knee down to a 7.5" leg opening. It is the most neutral frame the brand offers for a fabric with this much texture.

Woven in Okayama on shuttle looms, with a button fly and iron buttons, hidden rivets on the back pockets, herringbone twill pocket lining and a chain-stitched hem and waistband. Unsanforized and one-washed. Made in Japan.

Fit Notes: Pure Blue Japan sizes usually run a bit small compared to most global American brands, and this pair slightly more so: the waist measures at or just under the tagged size. We recommend going one size up from your usual size, or taking your usual size only if you want a snug, slim fit from day one. The cut is a slim straight with a mid rise that sits just below the natural waist, slightly slim through the seat and thigh, and close to straight from the knee down to a 7.5" leg opening. The denim is unsanforized and one-washed and it stretches at the waist with wear (up to 1"). As always, we strongly recommend checking our size chart and comparing it with your best-fitting garment to ensure the right fit.