On a Saturday afternoon in Seongsu-dong, the former industrial district on the east side of Seoul, the queue outside a small concept store stretches past a shoe repair stall and around the corner of a converted printing factory. Nobody in it is dressed casually. A young man wears a cropped tweed jacket over a hooded sweatshirt and wide pleated trousers. The woman behind him has paired a vintage wedding veil with cargo shorts and hiking boots, and nobody seems to find this remarkable.

Seoul has become one of the most influential street style cities on earth, and its influence moves fast. Looks that appear here on a Saturday are often reproduced by fast-fashion chains within weeks and sighted in Paris, London and New York by the following season. Yet the city's fashion culture remains strikingly local, built on small independent labels, tiny shops hidden above noodle restaurants and an obsessive, collaborative online community.

The shop is the studio

Yoon Seo-ah, a stylist who works with many of the city's younger labels, says the key difference is proximity. In Seoul the designers are often the shopkeepers, and the customers are often friends. Studio Gaeul, founded by two former textile students, sells from a single room in Seongsu where the sewing machines sit behind the counter. Customers can watch the next batch being made, suggest changes and pick up altered pieces a few days later.

Here the feedback loop is a few metres long. You can change a collar on Tuesday and see it on the street by Friday. — Yoon Seo-ah

That speed creates an atmosphere of constant experiment. Proportions shift with remarkable frequency, from exaggerated oversized shapes to cropped, precise tailoring and back again. Layering is complex and often counterintuitive: a slip dress over wide trousers, a knitted vest over a shirt over a hoodie. Colour tends toward muted tones lifted by a single saturated accent, while hair clips, small bags and oversized scarves carry much of the personality.

There is also a deep respect for craft. Several young labels work with traditional Korean techniques such as quilting, knotting and natural dyeing, and reinterpret them in contemporary silhouettes. Pale Ink, based in a small studio near the old palace quarter, has built a devoted following for jackets made with hand-quilted cotton padding, a technique long used in winter clothing. Each small release sells out within hours.

The pace has its critics. Some local designers worry that the city's appetite for novelty is exhausting and wasteful, and that small labels are burning out trying to keep up. A growing counter-movement favours slower, seasonless collections built around repair and resale. Yoon sees the tension as healthy. The city, she argues, is working through in public the same questions the entire fashion industry is struggling to answer.

By early evening the queue in Seongsu has thinned and the streetlights are coming on. A group of students photograph each other against a graffiti-covered shutter, adjusting a scarf here and a sleeve there with the concentration of a professional shoot. Tomorrow some of these images will circulate around the world. The looks will be copied, and by then, inevitably, the side streets will have moved on to something new.