Sumo wrestlers play baccarat Wednesday at Mandalay Bay, site of a three-day exhibition of the Japanese sport. Photos by John Locher. Wass Coulibaly, left, a dancer in "Zumanity," kisses a sumo wrestler Monday after having her picture taken with him at New York-New York on the Strip. Several sumo wrestlers attended the show and met the cast afterward. A sumo wrestler cheers on his friend as he chugs beer at a welcoming dinner on Thursday for the Grand Sumo Championship Las Vegas, which commenced Friday at Mandalay Bay. A young fan reacts as sumo wrestlers walk past her on Thursday at Mandalay Bay. The wrestlers are competing in the Grand Sumo Championship Las Vegas, which runs through Sunday.

They are here, unabashedly fat and half naked.

They are 38 of Japan's top sumo wrestlers, participating in a spectacle this weekend the likes of which Las Vegas never has seen before.

The pudgy giants have been turning heads in and out of the ring during their historic trip to the Strip to participate in the Grand Sumo Championships at Mandalay Bay. It marks the first time in two decades that the three-day exhibition has graced U.S. soil.

There were sumo sightings this week at the adult-themed "Zumanity" show, including one wrestler who was brought onstage as fodder for the cast.

Some sumos goofed around or sunbathed poolside. Others, dressed in their mandatory public attire of silk robes and samurai-style hairdos, played baccarat and blackjack.

"I'm losing in gambling, but I would like to win in sumo," said Asashoryu, a 322-pound Yokozuna, the ultimate ranking for a sumo wrestler.

On the eve of competition, which began Friday night, some sumos strayed from their traditional meal of chanko-nobe, or a meaty stew, and feasted on sushi and other Japanese cuisine.

Japan's national heroes clash again tonight as part of their campaign to transform America's view of the 1,500-year-old sport from a source of comic relief to a highly regarded competition.

"It's a chance for the American people to discover what Sumo really is. It's not just fat guys in diapers dancing in a circle," said Hiro Ichioka, one of dozens of Japanese journalists covering the competition.

The athletes' training regimen ranks among the most structured in the world. Many sumo wrestlers begin training at age 15, rising before 5 a.m. to perform chores. All are subject to a strictly enforced code of conduct and, unless they are married, live in dormitories with their teammates.

Diet is also key to excelling in the Japanese national sport.

Most sumos consume 5,000 calories a day, with 10,000 calories a day not uncommon. Sometimes beefing up requires force feeding.

Konishiki, a retired sumo and native Hawaiian, recalls one teammate who had to eat chanka-nobe and then down 10 bowls of rice daily.

"They actually sit there and watch you eat," Konishiki said, referring to coaches. "That's a lot of work."

Midday naps follow the huge meals and are vital to packing on pounds, he said.

Konishiki moved to Japan at age 18 to train. He weighed about 280 pounds at the time.

"I got to 600 (pounds) by the end of my career," the 42-year-old said.

Over time, the sumo's body evolves. Fatty, slumping pectorals and protruding bellies are common, as is a sagging posterior. But such frames belie the tremendous athleticism of elite sumos.

This is evident when people see them compete in person.

As sumos entered the small clay circle where they competed Friday night, they practiced a series of mandatory rituals.

They clapped their hands, which, according to ancient sumo tradition, is said to grab the attention of the gods. The stone-faced competitors raised a leg and stomped the ground, which is supposed to chase evil spirits from the ring. The throwing of salt purifies the ring.

Then sumo opponents squat in front of each other for a stare-down.

The stare-down, stomping and salt-throwing can carry on for minutes. But once a match is under way, it is often over in a matter of seconds.

The sumo wrestlers fire off the line and lunge at each other. It is a violent explosion of flesh colliding, often accompanied by a loud slapping sound.

Small sumos with superior technique often defeat their bigger foes. Some sumos win by pushing their opponents out of the circle. Others lift or hurl them out of the circle.

In contrast to American sports, winners rarely show emotion in victory.

And it is unlikely that the legions of bettors in Las Vegas will be showing any emotion, either. Mandalay Bay is playing host to the sumo event but will not take bets or give odds on the action.

It remains to be seen whether the Japan Sumo Association can change Americans' perceptions of the sport.

Promoters of the event might be hard-pressed to lure mainstream Americans without resorting to the old, humorous stereotypes. This was evident when John Melendez, a sidekick to Jay Leno on "The Tonight Show," went against a sumo as part of a skit. "I'll have you know," a bare-chested Melendez told his supersized adversary, "I watched 'Karate Kid' 27 times."