The “uncanny valley” is a robotics term dating back to Japanese professor Masahiro Mori in 1970. It hypothesizes that as a robot takes on more human characteristics — eyes, a face, five fingers, weird Terminator-esque skin — there’s a certain threshold where your response to the automaton turns from empathetic to strong revulsion.

In other words, there’s a line between barely human and fully human that tends to gross people out. And one particularly polarizing Japanese-inspired shoe from designer Martin Margiela may prove that fashion has an uncanny valley too.

Let’s go back to Paris in 1988. A time before the Internet and Instagram turned fashion into an integral part of pop culture. Back then, the industry was still a closely-guarded secret, only accessible to a privileged few. But even then, fashion had its iconoclasts, and Belgian designer Martin Margiela’s debut show marked a paradigm shift.

His Spring/Summer 1989 collection included pieces like a leather butcher’s apron turned into an evening gown. A tulle dress was deconstructed and transformed into tailored jackets. The design language, at least to the eye of a fashion enthusiast, demonstrated that Margiela had an astute understanding for the rules of how clothing should be made—but chose to ignore them completely.

Abdul Abasi, co-founder and designer at Abasi Rosborough, is one of many designers who regards Martin Margiela as one of the greatest of all time.

“A lot of people who wore Margiela to a typical fashion customer might actually look like they don't know how to dress. A lot of his things looked wrong on purpose. He did a whole collection on he made down coats that looked like duvet covers. So it's one of those things where he was almost more of a conceptual artist than a traditional designer.”

With that in mind, it’s no surprise that Margiela, a designer known for pushing the boundaries of beauty and romanticizing the grotesque, would take a humble Japanese workwear shoe and turn it into an object of desire.

Margiela’s tabi boot, largely based on the affordable Japanese “jika-tabi” shoes still worn by Japanese construction workers, features a circular heel, metal clasps known as “kohase” at the rear closure, and a signature split toe at the front. The big toe goes on one side, with the remaining four housed in the other. They’re essentially upscale ninja shoes that give the foot a cloven hoof appearance.

According Dominik Halas, Men's Merchandise Manager at Archival Expert at fashion consignment platform TheRealReal, the shoes made their debut in Margiela’s first collection. The soles were dipped in red paint, marking the white fabric runway as models walked it. The following season, that material was cut up and turned into a dress, further reinforcing Margiela’s idea of re-use and reinterpretation.

“I think it was really impactful because it's such a divisive style. There's so many people who loved it and so many people who hated it and found it so creepy. And I think that just speaks to a lot of what Martin was doing in his imprint on things, especially with how he was reworking vintage pieces. It's really that philosophy of making something that people weren't expecting or didn't necessarily find intrinsically beautiful and reworking it into something intellectual that stuck with people.”

Being a Margiela acolyte felt like belonging to a secret club. According to Halas, fashion at the time of Margiela’s debut was still largely extravagant, although the rise of Japanese designers like Yohji Yamamoto and Rei Kawakubo alongside the likes of Ann Demeeulmeester and Margiela heralded a new movement towards redefining aesthetic standards.

The Tabi boot encapsulated these anti-beauty ideas perfectly, conveying desirability and sexiness on its own terms. Kate Marin, branded fashion editor at Bustle Digital Group, sees that self-assured attitude and rebelliousness as something plenty of women are ready to embrace. They’re shoes stylish women wear to impress themselves, and not anyone else.

Further, Marin continues, Tabi boots represent a special kind of grail to certain women. In the world of status symbols, where flashy logos, monograms, and it bags instantly convey a wearer’s interests and income, Margiela’s Tabi has become a subtle signifier of discerning taste and culture.

“Tabis are really the only thing I can think of maybe other than a Birkin bag that's really like a grail piece for women. To even own Tabis you have to be pretty far along in whatever fashion journey or on like have a certain level of fashion education. So typically I feel like people who wear Tabis generally have a more like elevated sense of style..understanding of not only the history of Tabis, but generally like the history of the clothes that they like to wear. When you see someone in them—you know that they know what you know.”

To learn more about what makes Margiela's tabi boot an unconventionally timeless fashion grail, listen to the full episode of Why It's Cool.