Through the front door of a slightly fogged glass storefront, past a couple of racks filled with issues of Jiu-Jitsu Magazine, past several cubbies stuffed with colorful shoes and socks, past a white wall with a large yin and yang symbol, through a giant keyhole-shaped archway, and down a flight of cold iron steps, is the Rat Cave. That’s where René Dreifuss, the founder of Radical MMA, a mixed martial arts studio a couple blocks south of Penn Station, is teaching his 7:30pm judo and jiu-jitsu class.
He’s on the mat showing one of his students an arm bar, a grappling technique that involves cranking an opponent’s outstretched arm until their elbow hyperextends. “If I do more, I’m going to smash his arm to bits. And I know this non-theoretically. I’ve felt a guy’s arm explode between my legs. Literally, it was like firecrackers,” says Dreifuss, before making little crackling noises. “You have this thing called the bursar sack and fluid just explodes out. That’s what happens when you do an arm bar right.”
Dreifuss has a black belt in Brazilian jiu-jitsu, among several other disciplines. BJJ is a martial art that involves subduing an opponent using leverage, with a heavy emphasis on grabbing, throwing, and twisting limbs. He earned the nickname Ratão, or Big Rat, while training in Brazil in the mid-aughts, though he’s not sure why. “They keep saying it’s a good thing, but I think it’s not. And you can’t really argue,” he says with a laugh. “I think they think I’m a dirty rat maybe, I don’t know.”
It might be the power of suggestion, but the 47-year-old Dreifuss does have some rat-like features. He’s 5’7” with a thick torso and compact limbs, he’s got a pointy nose and big oval ears, and he speaks in a soft but squeaky voice, saying things like “Ohh, nice head drop!” and “Take his back!” to his students. Dreifuss is handsome, though, in an adorable way, with greying black hair, olive skin, and dark eyes.
Either way, Dreifuss is known as Big Rat, and has smartly incorporated the mousy moniker into his personal brand. After being hit by a car in Japan in the late ‘90s, Dreifuss suffered nerve damage that led to paralysis in his left leg. Still determined to fight, he adapted an old Judo position to compensate for his lack of mobility. He called it, of course, the Rat Guard.
“Its primary purpose is to protect yourself efficiently from strikes, which can be difficult with a very skilled opponent,” he says. “It’s a way to control the person’s posture and his ability to hurt you. It became very popular.” In fact, the position has since been used in the Ultimate Fighting Championship (UFC), the world’s top MMA organization.

Dreifuss demonstrating the Rat Guard with one of his students. The technique involves tucking your opponent’s head underneath your armpit.
Dreifuss was the victim of violence growing up in a predominantly Catholic neighborhood in Queens, NY. “In the ‘70s, life was a little bit tougher,” he says. “I was bullied very badly. It was discrimination because my dad is Jewish.” At the age of five, Dreifuss started studying martial arts to get tough. He watched a cable TV program called Drive-In Movie, which aired old Kung Fu flicks with voice-overs. When his father saw him emulating techniques in front of the television, he enrolled Dreifuss in a karate academy.
“For the first month, I wanted to quit because I was crying ever day coming home, but after a month, I stuck with it,” he says. “There would be blood all the time. I remember my first experience with my old sensei. He didn’t hurt me, but he kicked me hard enough for me to fly through a really thin wooden wall.”
Dreifuss slowly developed a love for martial arts. He decided, by the age of 14, that he would eventually live in Japan because he admired their way of life, specifically the culture and language. He went to Bronx High School of Science to study Japanese, and eventually got a joint degree in East Asian Studies and Political Science from New York University.
In 1992, the day after his college graduation, he left for Japan, or as Dreifuss calls it, “the motherland.” He lived in a foreigner house in Tokyo with other martial artists and worked as an English teacher. As soon as he became fluent in Japanese, reading and writing, Dreifuss became a translator. In 1998, he was planning to make his MMA debut.
But then, while riding his bicycle to work, he got t-boned by a car. Dreifuss remembers waking up in the grass, being in a lot of pain.
“They completely destroyed my bicycle. It was a heap of junk when it was done. I did a front roll over the hood of the car, they tell me. I’d be dead if I didn’t do that because my bike was just mangled.”
Although he suffered some fractures, and nerve damage in his left leg, Dreifuss didn’t tell anyone about the accident because he wanted to fight. Eventually, the injury was impossible to ignore. “It got worse and worse, to the point that I couldn’t feel my left leg,” he says. So Dreifuss travelled back to New York for surgery and the doctors removed the damaged nerves.
“It was kind of a happy accident,” he says. “It made me enter the world of Brazilian jiu-jitsu.”
In December 1999, he went to visit his sister in Redondo Beach, California. It turns out she lived a few blocks from one of the best BJJ school in the country, Machado Jiu-Jitsu. The training was great rehabilitation for his leg, but it involved a bit of an adjustment.
“I got the crap kicked out of me, and not because my leg was bad. These guys were flying F-15s and I was in a Wright brother’s Kitty Hawk. It was a technological leap in the submission game, which means joint locks and chokes.” Little by little, Dreifuss was able to train around the limitations of his body and learn the art of BJJ.
Today, Dreifuss describes his left leg as “clunky,” but it doesn’t seem to inhibit him as he walks around the Rat Cave. There’s no air conditioning or natural light in the windowless basement, just a row of overhead lights that stretch the length of the room and cast shadows on the blank walls. The floor is covered with dark grey tumbling mats, which are slick with body-shaped trails of sweat. In pairs, his students jostle on their feet before falling to the ground in a spider-like tangle of limbs. There are 14 students in the class, most of whom are civilians looking to learn the basics of self-defense. Dreifuss says his passion isn’t creating fighters, but taking normal people and making them feel safe walking down the street.
Danielle Hernandez is a performer and jewelry instructor. She takes Dreifuss’ Sunday self-defense class, which women can attend for free. Hernandez is barely taller than five feet, but Dreifuss has taught her multiple ways to stay safe in dangerous situations. “I’m not a body builder, but knowing the mechanics of my body means I have a solution for everything,” she says. “The only thing I know I can count on is myself and trusting the skills I’ve learned.”
Every so often, René asks his wife, Mariko Dreifuss, to help the students with technique. She’s a 33-year-old woman with black hair and an athletic frame. When Mariko, who is originally from Japan, met René 10 years ago, she’d never seen BJJ before. René told her that he could only date someone who respects his love of martial arts.
“Coming from a country where martial arts are not just hobbies but a lifestyle, I immediately understood,” says Mariko. She began following René to different gyms around the city where he was teaching. Eventually, she started training, too.
The couple lives in a small duplex apartment on the Upper East Side, along with their two cats, Asami and Kora. With the help of René, Mariko has gone from a timid newbie taking self-defense classes to a jiu-jitsu champion. She says one of his best coaching tools is the “bitter pill” of brutal honesty.
“If you suck at something, he tells you that you suck at it,” she says.
René tries to cultivate an environment of honor and respect at Radical MMA. There’s no wearing shoes or hats, and everyone who enters must wash their feet in a blue footbath containing medical solution. There’s also no swearing. Several times throughout the session, the word “Oss” is repeated, which, according to René, means “I will persevere through hardship,” and serves a similar function to the word “aloha” for Hawaiians.
“When you walk into this academy, you will be expected to be part of that samurai tradition. There’s a little piece of Japan here,” he says. “You will strive for focus, integrity, honor, and fair play. Just be the best version of yourself that you can be.”
René has a rigorous Japanese approach to training, according to Simon Ying, a student in the jiu-jitsu class. They met in 2005 years at studio called Fight House, where René was an instructor. Ying says that while René is a tough coach, he’s always respectful to his students.
“He’s very friendly, very open-minded,” says Ying. “He has an anti-bullying approach and it comes out in how he speaks to other people.”
In 2004, René had his first “underground” MMA fight. Back then, the sport was illegal in the state of New York and had a bad reputation for its violence. “It was still considered human cockfighting,” says René. The fight happened in a gymnasium in the Bronx, with a crowd of about 125 people, in a promotion called Underground Combat League: Manhunt. He faced a Muay Thai fighter named Richie Torres. The wooden floor was covered in taped-together mats, and they fought barefoot and barehanded under Vale Tudo rules, which means everything goes except for biting and eye-gouging.
“I actually made out my will and testament before I fought, because I wasn’t sure what was going to happen,” says René. “I probably went to the bathroom 700 times before the fight. I mean, it just wouldn’t stop. My hands were shaking, I couldn’t feel my toes, and that’s not the paralysis, it’s the nervousness. Then something just took over.”
The fight only lasted 58 seconds. René says he shot in, took Torres down, and mounted him from behind. Then he “unleashed a technical barrage of attack,” which included nearly 20 shots to the back of his opponent’s head. That forced the ref to stop the fight, and René was declared winner by TKO.
“I was channeling something special, I never felt that before,” he says. “I became a better version of myself. Not because I defeated someone else, but because I conquered my fear, my inhibitions. To this day, I walk around with much less insecurity.”
Along with his duel degree from NYU, René has a master’s in Japanese Military Studies from Columbia. While finishing school, he supplemented his income by teaching private jiu-jitsu lessons, never seriously considering a career in martial arts. He thought about going into academia and continuing his studies of Japan as an intellectual, until he realized that he doesn’t enjoy anything as much as martial arts.
“And that was the eureka moment where I said, ‘This is what I was meant to do.’ To the absolute consternation of my mother, who wishes I were a lawyer or something more respectable.”
In February 2014, René opened Radical MMA, where he continues to take a cerebral approach to teaching. “I’m not looking for barbarism, I’m not looking for brawling. I’m looking to problem solve any situation where I could be in danger. What is problem solving? It’s a puzzle, like anything intellectual,” he says. “Jiu-jitsu at its core is intellectual. It’s chess with the human body.”
Fantastic article and representation of a great martial artist and even better teacher. I studied with Rene for a year or so and couldn’t have asked for a better experience.