The contenders were itching for a fight.

They bolted up the path to the ring and snarled at each other with teeth bared. Then the bell rang - and they lunged at each other's throats.This was no fight between ordinary heavyweights: It was a brawl in a cherished Japanese tradition, endorsed by no less than the emperor himself: dog fighting.

At the center of the sport is the feared Tosa - a dog so powerful that it is banned in some places.

Animal lovers might balk at the violent tradition, but fans of the Tosa gush about its fighting prowess in terms usually reserved for thoroughbreds or fine wine.

"A good dog is very special, maybe only one in a thousand," said Masaru Hirose, owner of the Tosa Fighting Dog Center in Katsurahama, 600 miles southwest of Tokyo.

Dog fighting in Japan goes back to the 14th century, but Tosas were bred to their current form - with vise-grip jaws, a powerful chest and a nasty temper - in the 19th and early 20th centuries.

The dogs are impressive. With a short brown coat, full jowls and a stout, muscled physique, the dogs can reach 200 pounds and a height of 26 inches. A champion can sell for tens of thousands of dollars.

The rare canines are prized as strong, loyal guards by dog-lovers in the United States, and fans have formed the International Tosa-ken Association.

But Tosas are also fighting machines.

"Clearly, it is a dog for only very experienced dog-handlers," reads a description put out by World-Class-Dogs Inc., adding that the breed is banned in Britain. "It is powerful, stoic and relentless."

The Japanese government has tightly controlled the fighting tradition. Gambling is now banned, and Hirose's dog center along the rocky south coast of Shikoku Island is the country's only licensed fighting center.

Periodic title matches, however, can be held elsewhere, and Tosa owners are all over the country. Prized fighters are given the same titles as venerated sumo wrestlers, with top dogs given the "yokozuna," or grand champion ranking.

In a match put on for reporters at Hirose's center, the dogs bolted across a bloodstained canvas and attacked each other at the throat, standing up on their hind legs.

The dogs - scarred on face and legs from earlier matches - growled and salivated as they sank their teeth into the loose, almost elastic folds of fur around each other's necks.

At title matches - held at makeshift rings around the country - more than 100 owners and trainers watch as top Tosas duke it out in bouts that can run as long as 30 minutes.

A dog loses when it yelps or tries to flee. Judges declare winners and hand out rankings.

Though dogs are often hurt, owners say they don't let the fights get out of hand.

Officials at the dog center say they've never heard of a Tosa being killed in a match.

But pulling apart the fiery canines can be difficult. At the end of the match at Hirose's center, two trainers leaped into the ring and grabbed the dogs by the tail as a third trainer jutted a flaming torch in their faces.

The isolation of the sport's lone training center on Shikoku has kept it off the radar of Japan's tiny animal rights movement.