Reika Yo of Tokyo and Martin Shapiro of Brooklyn have found common cause in Manhattan.

That cause is the sustainable development of downtown, where Ms. Yo runs an acclaimed restaurant that will soon celebrate its second anniversary, EN Japanese Brasserie. Mr. Shapiro, a well-known restaurateur who once ran the popular discothèque Regine’s, is managing partner of the Tribeca Grill, a local landmark for the past 16 years.

“It’s not as though this is a depressed neighborhood, but downtown has recovered far less rapidly from the tragedy of September 11, 2001, than other areas of the city,” Mr. Shapiro said. “The meatpacking district, or the Lower East Side, they seem to have attracted a lot more shops and restaurants, but downtown has a special vitality. I’m very optimistic.”

Ms.Yo is optimistic, too.

“I could have opened my restaurant somewhere else in Manhattan — in Midtown, or the Upper East Side. I like SoHo, but I found spaces there too narrow,” she said. “I liked downtown’s character. This is a very peaceful area, and it has a destiny. I like the sense of space and serenity here.”

As New York restaurants go, Ms. Yo’s facility is spacious. She can seat 190 diners in EN’s 6,000 square feet. Mr. Shapiro’s restaurant has commodious space, too: 8,000 square feet that can accommodate 200 diners at ground level and 120 upstairs.

These diners often include celebrities. Indeed, the principal owners of the Tribeca Grill are the actor Robert De Niro — who is also building a hotel abutting the restaurant — and celebrated restaurateur Drew Nieporent. Ms. Yo’s restaurant often attracts visiting movie stars and corporate tycoons from her native Japan, where her brothers Bunkei Yo and Bunko Yo manage 30 branches of EN Japanese Brasserie.

This being Restaurant Week in New York, the traffic of diners was especially notable. Both Ms.Yo — whose restaurant is open only for dinner — and Mr. Shapiro were emboldened to suggest that the concept might be extended beyond the current two weeks in July and another two weeks in January.

“There’s been an explosion of restaurants in the city since the mid-1990s,” Mr. Shapiro said. “The majority of restaurants in New York are not packed on a nightly basis. Most restaurants need to fill every seat twice a night to be profitable. So Restaurant Week is a great opportunity, a win-win situation for both customers and restaurateurs.”

The concept was launched in 1992 and is promoted by NYC & Co., the city’s official tourism marketing organization. More than 200 top restaurants offer daily prix fixe lunches for $24, and dinner for $35. The concept has spread to a dozen cities around America.

It has even spread to Tokyo.

“Diners learn that Japanese food consists of more than just sushi,” Ms.Yo said.

Among other things, it consists of “izakaya,” a concept reminiscent of the Spanish tradition of tapas, where diners partake of small portions from a variety of dishes such as freshly made tofu. In Japan, an “izakaya” establishment traditionally serves as an after-office-hours place for food and drink — not quite a full restaurant, but something more than a bar.

Ms. Yo was determined to expose New Yorkers to “izakaya.” So she moved to America, bringing with her two Japanese chefs and the support of her brothers.

She did not arrive in the city a novice in the restaurant business. Her father, Eimei, operated several restaurants in Japan, and Ms. Yo and her brothers grew up exposed to restaurant talk at the family dinner table.

Occasionally, the talk was also about medicine.

That was because Eimei Yo was a trained physician.

“He gave up medicine to make more money in restaurants,” Ms.Yo said.

Mr. Shapiro said his father, Herman, also was a physician.

When Ms. Yo heard that, she expressed amazement.

“Here we are, discussing the development of downtown Manhattan —two people from different cultures and different countries, each with a father who was a doctor,” she said.

As they conversed, it came out that Ms.Yo and Mr. Shapiro had other things in common, besides being single. Ms.Yo studied classical jazz in London and was an accomplished pianist who gave recitals for nearly a decade before entering the restaurant business. Mr. Shapiro, a graduate of the University of North Carolina, earned a degree in theater and worked on the New York stage and in film for a decade before entering the restaurant business.

“Obviously, there are similarities between showbiz and the restaurant business,” Mr. Shapiro.

Ms. Yo agreed that the restaurant business is all about being in the limelight every minute of the evening.

“I’m glad that I studied jazz, and that I learned to improvise on the piano,” she said. “Running a restaurant involves a lot of improvisation.”

Their professional lives have converged in downtown, the area that Mr. Shapiro especially identifies as TriBeCa, and which for Ms.Yo includes the swath arcing below Canal Street and embracing neighborhoods up to the financial district.

“This is a very community-minded neighborhood. It has maintained its character, and really hasn’t gotten commercialized,” Mr. Shapiro said. “Maybe that’s why it hasn’t recovered as quickly as other parts of the city.”

The optimism that he expresses has less to do with the possibility of expanded commerce than it does with that of more residences in the area. He suggests that as the economic development of the ground zero area accelerates, there is bound to be a spillover into TriBeCa and the rest of downtown.

That is why he expresses admiration for entrepreneurs who have invested in the area, such as Ms. Yo.

“It’s comforting to hear about her passion and commitment,” Mr. Shapiro said.

“I’m in it for the long term,” Ms. Yo said. “There is nothing quite like New York — and downtown is the place to be right now.”