BEVERLY HILLS, Calif. » One of the country’s most renowned sushi restaurants, Urasawa, sits in a small alcove above Rodeo Drive here. A typical bill for two people easily tops $1,000. Over an evening that can stretch to three hours, diners are served dishes dotted with caviar and 24-karat gold flakes (for the iron, the chef notes).

But workers in the back kitchen are routinely denied overtime pay and forbidden from taking breaks, according to former employees and a California Labor Department investigation. Now, the chef and owner, Hiroyuki Urasawa, is battling state and civil claims that he withheld tens of thousands of dollars in wages and overtime from workers. One former employee who left the restaurant last year said he resorted to urinating in the sink meant for cleaning mops after being told the men’s restroom was for customers only during business hours.

Each night, Urasawa stands behind a pristine sushi bar serving more than a dozen dishes, each with an elaborate description of the provenance of the ingredients, mostly imported from Japan. With an affable smile, he happily accepts sake from diners, who can spend hundreds of dollars on a bottle.

"It was always about the customers, making sure that they were happy," said Heriberto Zamora, 26, who worked at the restaurant for more than five years and has filed a civil suit for back pay. "None of the employees were treated very well. We knew people were paying a lot to eat there, but for us it was no different."

After emigrating from Oaxaca, Mexico, as a teenager, Zamora found a job at Urasawa through a friend. He worked his way up, starting as a dishwasher and eventually cleaning and preparing the fish and arranging precisely cut vegetables. After a promotion, while he was earning about $9 an hour, Urasawa forced him to buy his own $700 set of knives – each meant to touch only certain ingredients, Zamora said. Eventually, he was working nearly 60 hours a week for $11.50 an hour.

One day in June 2012, nine hours into his shift, Zamora was coughing and asked to go home, complaining of a fever, he said. Urasawa fired him on the spot, he said.

Urasawa and his lawyer declined to comment for this article. But he has appealed a ruling issued by the state last month fining him $55,000 for failing to pay overtime and give breaks to Zamora and three other employees.

Urasawa is not the first high-end chef to face charges from workers. Mario Batali and his partners ultimately reached a $1.5 million settlement last year with a group of employees at several of his restaurants in New York.

The Urasawa case has become something of a battle cry among the overwhelmingly immigrant work force in hundreds of kitchens here. Labor and immigrant advocates say Zamora’s experience is typical for thousands of workers in restaurants, regardless of how much customers might be paying to eat there.

The problem is particularly acute in businesses that rely on cash to pay workers, as many restaurants do. A 2009 study by the Labor Center at the University of California, Los Angeles, found that there was an average of $26 million worth of wage violations each week in Los Angeles.

"There are countless examples in which workers are taking home less than they’ve earned," said Julie Su, the state labor commissioner, who has made cracking down on wage violations a focus of her office. In the case of Urasawa and dozens of other restaurants, investigators wait outside watching workers come and go, comparing what they see to the time records kept on employers’ books. "It’s a perversion of the concept of minimum wage – it goes from being some kind of floor to instead being some kind of ceiling," Su said.

Su has investigated hundreds of wage violation cases this year, using individual complaints as starting points for many of the investigations. In countless cases, she said, owners rely on paying the same rate over 12 hours, though such practices violate labor laws created a century ago in part to ensure that employers hire a sufficient number of people, rather than rely on one worker for many hours.

"We see this happen all the time, across all industries, all parts of the city and all kinds of businesses," said Kevin Kish, a lawyer for Bet Tzedek, a nonprofit legal group that has taken on Zamora’s case. "The only thing that is remarkable about this case is that people might expect paying so much means that workers are getting paid fairly."

After Zamora was fired, a friend told him to go to the Koreatown Immigrant Workers Alliance, which helps many workers file wage violation complaints. This spring, the organization held a daytime protest in front of Urasawa, which garnered some attention in the local news media.

But by all appearances, there has been no backlash against the restaurant. Jonathan Gold, the influential food critic for The , named it the No. 2 restaurant in the city this year, with no mention of the recent controversy.

Reservations, which often are made weeks in advance, must be secured with a credit card, and diners are advised to cancel 48 hours in advance or face a $100 charge. On a recent Tuesday evening, nearly all of the diners were foreign tourists, including an Australian couple on their honeymoon and a group of friends from Shanghai.

They all seemed more than willing to abide by the rules set forth by Urasawa: no pictures of the food, sushi must be consumed within 10 seconds of being served and no copies of the itemized bill can be taken home. When he served them foie gras as part of a shabu-shabu dish, there was no hint of awareness that the goose liver had been banned in California for more than a year.

Two waitresses silently scurried about, making sure the customers never had to open a door or be without a hot towel or a full glass of their beverage of choice.

Organizers at the Koreatown workers’ group said one waitress quit this year after Urasawa urged her to testify against Zamora during a hearing. Zamora said it was common to hear Urasawa yelling at employees of every ethnicity, calling them "baka" – Japanese for stupid.

In 2007, Zamora and two other employees left briefly, frustrated about the conditions. He found a job at another sushi restaurant, but he was working fewer hours with a less dependable schedule. Urasawa called him a few months later, saying he did not want to train another employee.

"So I went back," Zamora said. "It was better for a while."

Within weeks, Zamora said, he was back to 10 hours on his feet. But he stayed, unsure if he could find another job earning roughly $600 a week. Still, he was already frustrated when he complained about being sick last summer. "He told me there were many other Latinos who would be lined up for my job," Zamora said. "I didn’t ever consider going back."

Zamora keeps a picture of himself standing in the Urasawa kitchen in a yellow kimono with Japanese sandals. He has his set of knives, too, sheathed in a black case he once took on his hourlong bus commute each day. They look a little worn, the sheen mostly gone. He cannot remember the last time he sharpened them. These days, he uses them only once in a while, to make carne asada.