There’s no underestimating man’s beetle-browed jones to exploit anything and anyone small and weak for fun and profit, so perhaps it’s no surprise that Thailand hosts a thriving sports culture centered on the kickboxing matches between eight-year-old girls. Kellstein’s pint-size doc tells us right off that there are some 30,000 girl boxers in the country, supporting a betting spectator-sphere that must number in the millions, and then it trains in on two such fighters, petite third-graders Pet and Stam, upon whose bludgeoning prowess and strong jaws depends thousands of wagered baht and even the fate of the family home. Little girls’ arms are routinely broken, we’re told, and their battle prep involves body oil and lipstick. How this mad nonsense got started—as a 21st-century upgrade from cockfighting?—is one of many larger questions Kellstein never answers. Like so many safe, “personal” nonfiction films, Buffalo Girls hews close to the experience at hand, which sometimes feels a little too much like a normal leading-up-to-the-big-game Undefeated-style sports doc. But there’s no missing Kellstein’s unstated horror during the fight sequences, which traffic in queasy blood sport absurdity that overshadows Battle Royale and The Hunger Games, because the cherubs are eight and because it’s all too real. Only 66 minutes long, Kellstein’s movie could have tackled an entire culture’s disposable misogyny, but instead gives only a glimpse of girlhood as gladiatorship.