Shane Arechiga isn't big for a 12-year-old, but he throws down hard.

On the mats of the Yamasaki Academy, inside Kim's Karate in Springfield Mall, he easily grapples with, or lifts and then tosses down, larger and more experienced men. With three years of training, he looks like an expert in the martial art of Brazilian jiu-jitsu, which is rapidly gaining popularity in the Washington area.

"It's just fun," he said recently during a break from practice, though he casually admitted that he had used his self-defense training in real life. After a bully at his school in Maryland punched him, Shane quickly put him on the floor without throwing a punch, according to his father, Tod Arechiga.

And that's what distinguishes Brazilian jiu-jitsu from other martial arts, its proponents say. The niceties of form and philosophy in an ancient martial art won't help when a mugging, bar fight or sexual assault puts a person on the ground or in a brutal clinch, as such real-life altercations often do. Brazilian jiu-jitsu teaches not only how to throw -- or pick up and toss down -- an opponent, but also how to fend off one who is on top or is trying to punch or choke, and how to force an attacker to submit by cutting off breathing or controlling key joints.

"All the others are standing martial arts," emphasizing stand-up fighting, said Fernando Yamasaki, whose Brazilian family has established growing outposts in Springfield, Chantilly, Leesburg, the District and Rockville. "Our jiu-jitsu was taken from the street fight," which focuses on submission and ground fighting.

Francisco Neto, one of Yamasaki's instructors and a native of Sao Paolo, described it as "an evolution of martial arts. All the teachers [of other techniques] kept it the traditional way, the way they used to do it 2,000 years ago. Brazilian jiu-jitsu made it practical."

There is no strong emphasis on a certain philosophy, or chi, or "wax on, wax off," as the instructor in "The Karate Kid" films famously said. But a mental strength and confidence clearly develop among Brazilian jiu-jitsu devotees, along with the camaraderie of having shared brutal sessions of sparring, grappling and maneuvering.

"You have to constantly work with changing circumstances while you stay focused on overcoming the challenge of a match," said Mike Casey, 41, of Oakton, who took up the sport two years ago and won a gold medal in his division at the world championships in Rio de Janeiro in August. "What I found is formerly stressful situations aren't stressful anymore. Because when you fight someone who's trying to choke you or break your arm, office [problems] just aren't that big a deal anymore."

Brazilian jiu-jitsu academies are springing up all over Northern Virginia and throughout the state, said Gustavo Machado, president of the Virginia BJJ Federation. "Virginia and D.C., it's growing so much. I'm really surprised with the growth," Machado said. In launching a tournament in Virginia Beach next month, Machado said he sent invitations to 50 Brazilian jiu-jitsu academies around the state.

The sport evolved in the transplanted Japanese culture in Brazil in the 1920s and '30s, led by a man named Helio Gracie. Yamasaki said Gracie would travel from town to town, challenging all comers to fight him in the style of "vale tudo," or "anything goes."

Soon, Gracie and some of his six sons began teaching their revised version of jujitsu, a Japanese form of wrestling, at academies in Brazil. They later began opening schools in this country, and Rorion, Rodrigo, Rickson and Royce Gracie are now revered masters of the sport.

Its popularity began to grow when the Gracie family and jiu-jitsu's followers discovered the "Ultimate Fighting Championship," violent American bouts often seen on pay-per-view television. The Gracies and others participated in the TV contests, dominating bigger, stronger men and winning championships. Word spread, and fighters who once specialized only in boxing or karate added Brazilian jiu-jitsu to their repertoires.

Competitors in Brazilian jiu-jitsu tournaments wear a heavy, judo-style martial arts uniform. The goal of the sport is to force an opponent to submit, which he signals by tapping his opponent, the mat or himself three times because he is choked, or feels close to having an arm or leg broken. There is a scoring system similar to wrestling if there is no tap-out at the end of a single-round match, which lasts from five to 10 minutes, depending on the level of the competitors.

Kristen Allan, 22, of Springfield, a judo competitor who hopes to reach the Olympics, said she also practices Brazilian jiu-jitsu as "great cross-training for judo. Even if I'm not going to use the exact techniques, it's going to help me improve."

Law enforcement agencies, including the FBI and the Drug Enforcement Administration, have sought training from the Yamasakis, and Brazilian jiu-jitsu academies have assisted police and sheriff's offices around the country.

Tod Arechiga, 42, a D.C. police officer who lives in Aspen Hill, said that the sport "gave me the confidence that the police department doesn't give you, to not have to go to a weapon" when facing dangerous situations. He said a lack of training in hand-to-hand fighting left D.C. officers feeling that they had to resort to their gun, causing crime suspects to respond in kind. "The result was a whole decade of police shootings."

Joe Cunningham, 32, of Alexandria said he has been training for seven years. He said he was a longtime recovering addict and often brought in youths who needed a more healthful outlet.

"It usually has a good impact on young kids," Cunningham said. "You don't want to teach thugs how to fight. But thugs don't last here."

Casey, a public relations consultant, took up the sport two years ago out of curiosity and as a way to stay in shape. Soon he was hooked, training up to five times a week in addition to his cardio workouts.

But Casey said he had no intention of competing, until Fernando Yamasaki practically goaded him into it when other students were preparing for an international tournament. In a hot, noisy gym at the world championships in Rio in August, he lost his first fight in his weight class in a controversial scoring decision. He wound up winning a bronze medal.

Discouraged, he wanted to stop, but his father and Yamasaki urged him to continue. He then competed in a tournament of all weight classes, not just his own, and won the gold.

"They call it the pit bull of martial arts," Casey said, "and that's not for nothing. A lot of the game is hanging in there longer than you think you can, which of course has a lot of application to difficult situations in your life. I've found that Brazilian jiu-jitsu has now become a way of life."

As have many devotees, brothers Mark Jones, 35, and Brian Jones, 29, of Centreville became intrigued with the sport after watching Brazilian jiu-jitsu fighters in the "Ultimate Fighting Championship." Both have worked as guards in the Fairfax juvenile detention center and said the self-defense skills gave them a confidence and ability to handle tough kids that they hadn't acquired in their standard guard training.

The Yamasakis have about 330 students in the Washington area. Jeremy Lafreniere, who operates the Capital Jiu-Jitsu Academy in Alexandria, said he has 160 students, and "we are growing."

Lafreniere said a lot of the students "come from military backgrounds, especially the Army, which has adopted Brazilian jiu-jitsu in the area of its combative training program."

FightWorks in Sterling has about 40 students, double the number since the start of the year, owner Dan Wallen said. "People are in tune with the idea that the great kicks you see in most martial arts are not the reality on the streets," Wallen said. "Brazilian jiu-jitsu is also phenomenal exercise, and you use a lot of muscles."

Beyond the physicality is an undeniable bonding that takes place among students of the sport. Wallen attributed that to the Gracie clan, who have been generous with their time and expertise and who he said have a natural friendliness that he often found on his trips to Brazil.

Fernando Yamasaki, a third-degree black belt who Casey said could be as tough as a drill sergeant in training, was relaxed and easy-going off the mat.

"I try to always be smiling, try to make life simple, the way jiu-jitsu is," Yamasaki said. "That's the way I try to teach. I try to make life simple."

Students work on Brazilian jiu-jitsu at the Yamasaki Academy, inside Kim's Karate at Springfield Mall. Practitioners say it has real-life applications. Mike Casey, top, with Fernando Yamasaki, says Brazilian jiu-jitsu has reduced the stress in his life, "because when you fight someone who's trying to choke you or break your arm, office [problems] just aren't that big a deal anymore."Mike Casey of Oakton, left, who won a gold medal at the world championships in Rio de Janiero, works with his coach, Fernando Yamasaki, whose family has five academies in the area. Mike Casey, center, at the world championships in August. Casey beat Douglas Pereira, left, in his last fight for the gold, and Daniel da Cruz, right.