In a city where taxicabs prompt passengers to tack on a 30 percent tip, the notion of turning down a gratuity sounds almost heretical. But one restaurant in Midtown Manhattan says it has taken that less-traveled path by instituting a no-tipping policy.

At Sushi Yasuda, tips are not only no longer being sought, but they will also be returned if proffered, said one of the restaurant’s owners, Scott Rosenberg.

After 13 years of trying to provide an authentic Japanese dining experience, the owners decided a few weeks ago to adopt the profoundly un-American custom of including the cost of service in the price of the food, Mr. Rosenberg said.

“The reason we did it that way was because in Japan, that’s how it’s done,” he said. “We thought, ‘How great would it be when you go to a restaurant not to have to think about the tip?’ ”