In Little Miss Sumo, a new Netflix documentary short, women in Japan are taking the fight for gender equality inside the wrestling ring. The 19-minute film condenses the story of Hiyori Kon, a student and sumo prodigy pushing back against the age-old edict that prevents women from competing in the sport professionally. “I study gender theory,” Hiyori explains in Japanese. “We learned about many women fighting gender issues all over the world, but there weren’t many Japanese women. Japanese people don’t ask for radical change.”

Hiyori Kon and her teammates are an exception. They are determined athletes in a sport that traditionally and controversially does not allow women to compete professionally. But their love of sumo is a ticking time bomb; unless the rules change, they will be forced to retire at the age of 21. Hiyori believes that if female sumo grows in popularity, it will eventually be permitted at a professional level. It is this battle for basic equality that drives her to be the best.

Little Miss Sumo, directed by Matt Kay, focuses on Hiyori’s preparation for the Sumo World Championships in Taiwan. In the film’s opening minutes, she describes the demoralizing effects of growing as up a little girl who loved wrestling but knew she would one day have to give it up. Over fuzzy home video footage of Hiyori as a small child, wearing gym shorts beneath the ceremonial loincloth, the now 20-year-old narrates, “Boys can aspire to be professional wrestlers. They can easily see a future in sumo. After elementary school, girls tend to quit. There weren’t that many wrestlers little girls could look up to.” Onscreen, young Hiyori barrels into another pigtail-crowned first grader, propelling her out of the ring, or dohyo.

Sumo is rooted in ancient rituals that still guide the way it is practiced today, like the use of salt to purify the dohyo. The rules are simple, with each match lasting only a few intense seconds. As soon as a wrestler is forced out of the dohyo or touches the dirt-covered ground with any part of her body except the soles of her feet, the wrestler loses. Competitors wrestle barefoot to grip the ground with their feet.

Kay relies on beautiful slow-motion shots to convey the extreme strength and artistry required of each athlete. Flesh ripples against flesh, then against the sand with a hollow thud as Hiyori slips her toes underneath the ball of her male opponent’s foot. Calf muscles strain in a fight to remain erect against the force of another wrestler’s body weight. Unsurprisingly, a physical therapist informs Hiyori that knee injuries are the most common risk of sumo wrestling. With a grin, Hiyori retorts, “Because we’re too fat?” (Fat jokes are, according to the film, a common fixture in sumo wrestling—as the women board their flight to Taiwan, one of them deadpans, “I’m scared the plane might crash because we’re too heavy.”)

“ Boys can aspire to be professional wrestlers. They can easily see a future in sumo. ” — Hiyori Kon

The fight against sexism in sumo wrestling came to a climactic head last year when the mayor of a town outside of Kyoto collapsed in the ring at a local tournament. As several female EMTs rushed to offer him medical aid, the referee demanded they leave the ring and after they left, administrators sprinkled “purifying” salt on the ground. The incident sparked a widespread debate about the oppressive and archaic devotion to upholding the sexist ban.

When Hiyori makes it to the final round of the world championships, her Russian opponent appears to stand at least a full foot taller than her. It does not look good for our heroine. Hiyori is brought to the floor after a particularly heated struggle. Wiping tears from her eyes with a pink striped towel, she says, “Even if you’ve worked so hard, for so long, you can lose in a flash.” But for Hiyori, it was never about winning. “I believe that as a result of my hard work,” she concludes, “women’s sumo will stop facing discrimination. I will continue to strive for it with that belief.”