Call it an antidote to fast fashion: Japanese jeans hand-dyed with natural indigo and weaved on a clackety vintage loom, then sold at a premium to global denim connoisseurs, reports AFP. Unlike their mass-produced cousins, the tough garments crafted at the small Momotaro Jeans factory in southwest Japan are designed to be worn for decades and come with a lifetime repair warranty. On site, Yoshiharu Okamoto gently dips cotton strings into a tub of deep blue liquid, which stains his hands and nails as he repeats the process.

The cotton is imported from Zimbabwe, but the natural indigo they use is harvested in Japan – its colour far richer than synthetic imitations, according to Okamoto. He calls it a "time-consuming and costly" method, commonly used to dye kimonos in the 17th-19th century Edo period. Momotaro Jeans was established in 2006 by Japan Blue, one of a few dozen denim producers in the seaside town of Kojima, renowned for their artisan quality.

"We're very strict about all aspects of manufacturing," Japan Blue's president Masataka Suzuki told AFP. That includes "whether the sewing is done properly, and whether the dye is beautiful," making local craftspeople with traditional manufacturing skills indispensable. Their efforts do not come cheap, however.

A standard pair of Momotaro Jeans retails for around 30,000 yen ($200) while a silk-blend pair costs 60,000 yen. The brand's most expensive offering, woven by hand on a wooden machine converted from a luxury kimono loom.