If Japan throws its doors open to immigrants it might start looking like a certain neighborhood in Yokohama with multilingual street signs, ethnic eateries, and a babel of languages spoken in the streets.

At the heart of this unconventional neighborhood is the so-called Icho housing complex less than 1 km east of Koza Shibuya Station on the Odakyu Enoshima Line. Roughly 20 percent of the 3,500 or so households here have foreign backgrounds, many having arrived in the past few decades from Vietnam, China and Cambodia.

“One good thing about this area is that people are ethnically very diverse. Here, it’s normal for you to be different from others,” said Hoang Ha Nguyen Phan, a 28-year-old Vietnamese who came to Japan with her family in 1995 to seek political asylum.

Experts say the neighborhood epitomizes the idea of interculturalism, which could be essential to Japan’s survival as an economic power at a time when its birthrate and labor force are in decline.

The Icho complex, run by the Kanagawa Prefectural Government, became a magnet for foreigners after the establishment in 1980 of a reception center in the neighborhood for refugees from Vietnam, Cambodia and Laos.

Many decided to live in the complex because of its proximity to the reception center, which closed in 1997. Other residents include factory workers from Brazil and Japanese orphans who were left behind in China after World War II and began to be repatriated in the 1980s.

The Cabinet Office in February released figures projecting that Japan’s population of 120 million will fall to 87 million by 2060, and to 43 million by 2110.

“The biggest problem we have around here is that residents, especially the Japanese ones, are getting older and older,” said Hideki Hayakawa, who runs a volunteer organization that helps local foreign residents with daily tasks.

Hayakawa said that while foreigners continue to move into the Icho complex, Japanese tend to balk at the tiny apartments and inconvenient location. As a result, there is an odd demographic gap: The Japanese residents are graying and the foreigners are providing the dynamism.

“A neighborhood faces a crisis if there are few kids. So I believe foreign families with children will play an important role in keeping this area alive,” Hayakawa said.

Hayakawa’s group, Tabunka Machizukuri Kobo, or Studio to Create a Multicultural Neighborhood, organizes Japanese lessons, arranges interpreters for a nominal fee and runs errands for foreigners who don’t understand Japanese well. He set up the group in 2000.

Hayakawa has watched the complex’s fortunes evolve for longer than that. He said there were problems in the 1990s, when some Japanese residents came to resent the rapid influx of foreigners. Some complained that the newcomers ignored rules on taking out the garbage, for example, or that they would disturb the block with karaoke bouts late at night.

In 1999, the frustrations resulted in some Japanese petitioning the Kanagawa government to bar more foreigners from moving in.

But their animosity subsided in time, thanks to the immigrants’ own children. Raised in Japanese schools, when the youngsters grew up they taught their parents how to go local.

More than a decade later, the neighborhood could be facing yet another crossroads.

In April, the nearby Icho Elementary School, where many immigrants used to send their children, merged with the neighboring Iida-kita School because the Icho school had suffered a decline in enrollment. At its peak, it boasted a staggering 75 percent of pupils with foreign roots.

The merged and rebranded Iida-kita Icho School now has equal numbers of foreign and Japanese pupils, said Satoshi Kikuchi, a teacher in charge of intercultural education.

But not everyone is happy. Kikuchi said some Japanese parents from the Iida-kita school are worried that foreign children from the Icho school might be disruptive and force staff to pay them more attention than the Japanese pupils.

“We can’t give those foreign children the same amount of attention that the teachers at the old Icho school did,” Kikuchi said. “For now, we are focusing on educating both kids and parents on the need for interculturalism and asking for their understanding.”

One way the school may do this is by asking politicians or immigration experts to speak to parents about the values foreign residents bring to the community, and to explain that without them Japan will no longer be able to function as a strong economy, Kikuchi said.

“We’re no longer doing foreigners a favor by accepting them. We’re living in an age when we rely on them to maintain our economy,” he said.

The government of Prime Minister Shinzo Abe, it appears, shares Kikuchi’s view — at least partially.

Last month, it announced it will expand the controversial foreign trainee program by granting participants longer stays, extending their visa terms from three to five years. Although Japan rejects unskilled laborers from abroad under current government policy, unscrupulous employers often exploit the trainees as cheap labor.

The program is being extended to lure more foreigners to bolster Japan’s shrinking workforce at a time when the nation is gearing up to build new facilities and infrastructure for the 2020 Olympics.

But speaking on television in April, Abe denied that Japan would ease its immigration policies soon, saying foreign countries have found that it causes friction with local residents. Open-door policies have led to “many unfortunate incidents,” he said.

Abe conceded, however, that there is a need for more foreigner workers to meet strong demand for labor in the construction industry.

Keizo Yamawaki, a professor at Meiji University who specializes in immigration policy, said that while he himself is not opposed to expanding immigration, Abe’s plan to admit more foreigners merely to meet a labor shortage is shortsighted.

He said it is almost inevitable, judging from Europe’s experience with so-called guest workers, that some trainees will end up staying in Japan semi-permanently by overstaying their visas or that some may marry Japanese citizens and automatically acquire the right to stay. Therefore, he said, Abe may be opening the door to immigration anyway.

“Japan’s shrinking population is a problem that will persist even after 2020. In fact, the pace of the population decline will only accelerate. So admitting foreigners merely as a temporary, stopgap labor force misses the point,” he said.