In a city jammed with see-and-be-seen restaurants crawling with celebs (J.Lo! P.Diddy! Martha Stewart!) and staffed by chefs who are stars in their own right (Mario! Rocco! Jean-Georges!), it might be easy to overlook Masa Takayama's sushi restaurant. Tucked behind an unmarked door on the fourth floor of the new Time Warner Center in New York City, it has no windows, a no-cell-phone policy and an unlisted number.

And there is nothing else like it. People who shiver at the notion of dining on such Japanese delicacies as raw shrimp marinated in its own viscera need not drop by. But fearless sushi fanatics with fat wallets? That's another matter. Since opening his Manhattan eatery last February, Takayama, a transplanted Californian whose fans include Madonna, Nick Cage and Sheryl Crow, has been packing customers in at prices between $300 and $500 per person, which makes Masa's possibly the most expensive prix fixe menu in America. Inside its serene, Zen-inspired restaurant space, gourmands can belly up to the $60,000 hinoki-wood sushi bar for toro tartare with Iranian caviar or foie gras poached in sea-kelp broth. As Takayama, 50, explains it, "I want to make people say, 'Wow!' "

Wow, indeed. A divorced father of three who runs marathons, Takayama has become used to critics claiming $500 is an absurd price for raw fish. He insists that the high quality of his fresh ingredients is justification enough: His live crabs and shrimp come from Japan, the langoustine from Scotland and his orders for Iranian osetra caviar ($1,300 a kilo) are filled by Petrossian, the famed importer based in Paris. Furthermore, since Masa has no menu and changes its offerings daily, Takayama painstakingly tracks what each of his regulars has eaten in a journal. "It's a sensational restaurant," says Tim Zagat, CEO of the ZagatSurvey restaurant-rating empire. "Is it worth the money? What would you pay for a work of art that you love or for great seats at a Knicks game? If you have the money and it makes you happy, then God bless you."

Raised in a small town north of Tokyo, where his parents ran a fish market and catering business, Takayama, the second of five children, began helping his father cook for wedding feasts when he was a teenager. After high school, he snared an apprenticeship at a Tokyo sushi restaurant, where his training was exacting: "All the time, the boss shouts, like in the army, 'Who did this?' " Takayama says, laughing. "So many times I think I'll never make it."

He did, of course, and found that "I loved this job"—partly, he says, because "I met celebrities, high-educated, rich people." In 1980 he moved to Los Angeles and quickly attracted a following; limos lined up outside his restaurant in the mid-Wilshire district. When he opened Ginza Sushi-ko on Rodeo Drive in 1984, the limos followed. Reviewed by the Los Angeles Times in 2001, it earned four stars: "Perfection is almost impossible in a restaurant," wrote critic S. Irene Virbila. "But Takayama somehow achieves it." In 2003 he moved on to Manhattan.

Devoted to his calling, Takayama doesn't fret now when critics occasionally ask whether a trip to Masa (which can add up to $1,000 for two with wine, tax and tip) is a glorious indulgence—or sheer madness. "People who talk about the cost only, they never get it," he says. "But other people, they come to my restaurant, they eat, and they say, 'Wow! I understand.' "

Michelle Green in New York City