The list of prohibited moves is short: eye-gouging and biting are on there, chokes, kicks and head butts are not.
If you want, you can even pull out your opponent's protective cup and punch him in the groin, as one fighter did on the Ultimate Fighting Championship's recent Judgment Day pay-per-view special.
It's a rough sport - so rough that it has been banned in several states, including North Carolina, Missouri and Illinois, and New York state allows ultimate fighting only for those wearing protective headgear. It rages on elsewhere, though, including Augusta.
The Ultimate Fighting Championship will stage a pay-per-view event tonight at the Augusta-Richmond County Civic Center.
In ultimate fighting, men from the various combat sports - an improbably long list that includes obscurities like "pit fighting" and "pan crase" - fight in an octagon-shaped ring. You win when your opponent quits, the referee stops the fight, or when time runs out and judges award victory.
Jack Nilsson, an Augusta kick-boxer, will compete tonight in his second ultimate-fighting event. In his first, he learned how rough the sport can be.
Early in the bout, his opponent ripped Mr. Nilsson's left nostril, creating a tear that required nine stitches. Later, the opponent put his finger up Mr. Nilsson's other nostril, and the kick-boxer quit before he had matching scars.
Mr. Nilsson, a 32-year-old former Marine who works as a manager at Ryan's Family Steak House, is an alternate for the Augusta event. That means he will probably fight in a warmup match for the arena crowd before the pay-per-view telecast begins. The main event on the telecast, dubbed The Ultimate Force, pits 275-pound David "Tank" Abbott against 210-pound Vitor Belfort. Mr. Belfort, a Brazilian jujitsu fighter, won the heavyweight tournament at the previous ultimate fighting pay-per-view by pummeling a 335-pound wrestler.
While the hype around ultimate fighting is similar to that of professional wrestling, the atmosphere is different, Mr. Nilsson said. He has never been encouraged to ham it up or develop a ring persona, he said.
"It's exactly what they say it is," he said. "It's reality fighting."
The fighting is less theatrical, too. The premise of ultimate fighting might seem to promise quick, violent exchanges, but much of the fighting actually takes place in long clinches. The athletes grapple on the ground or up against the octagon wall, throwing short punches and elbows or trying to apply a submission hold.
If anyone appears to be getting seriously injured, the referees are quick to stop the fight.
In training for tonight's event, Mr. Nilsson has spent much time on his knees, punching, elbowing and moving across a heavy bag placed on the ground.
In the ring, the kick boxer practiced getting himself in position to choke an opponent.
"OK now - elbow, elbow, knee, knee, let's go for the choke," said Mike Carlson, Mr. Nilsson's trainer and manager, working with him during an early-morning training session. Mr. Nilsson trains six days a week with a regimen that includes running, weightlifting, drills and practice rounds of wrestling and kick-boxing.
Mr. Nilsson and Mr. Carlson said they had little time to prepare for the last fight and hope to do better this time. At one point, Mr. Nilsson staggered his opponent with two punches, but was too tired to move forward quickly and finish him off.
Mr. Nilsson shrugs off any notion that ultimate fighting is too brutal, no matter what the law is in New York, or how many stitches he has in his left nostril.
"It's like a normal competitive sport to me," he said. "It's no different than boxing."
What: The Ultimate Fighting Championship's The Ultimate Force
When: 8 tonight
Where: Augusta-Richmond County Civic Center
How much: $50, $35, $22.50, $15 and $10