TOKYO -- "I could have found work back at home, but the pay and benefits are better in Tokyo," said a 22-year-old woman who moved from her native Miyagi Prefecture to the capital to work as a nursery school teacher. "I also wanted to try living in Tokyo, at least for a while."

She is not alone. Among Japan's 47 prefectures, 40 had more out-migrants than in-migrants in 2018, according to a report by the Ministry of Internal Affairs and Communications. 32 of those had more female than male out-migrants.

Of the seven prefectures that had more in-migrants, Tokyo and four other urban prefectures saw more women than men come in.

Japan's tight labor market means there are plenty of jobs in urban areas, and more young women are setting out in search of opportunity. That is a problem for the country's rural areas, which are already struggling with aging and shrinking populations, along with cities receiving disproportionate numbers of men and women.

The movements are so lopsided that they "could affect the number of marriages and children," said an official with Aichi Prefecture's Policy Planning Bureau. Aichi, home to Toyota Motor and other manufacturers, gained twice as many male in-migrants as female.

Young women generally move to cities close to their hometowns. Those from the countryside in eastern Japan tend to go to Tokyo, while many from western Japan head to Osaka. Tokyo has an especially powerful pull; it gained 6,165 more young women than men last year.

Those who came to Greater Tokyo have something of an independent streak, according to a 2015 government survey of young people there. More than 27% of young women said they took jobs away from where they grew up because they wanted to get away from their parents and hometowns. That's nearly twice the number of men who gave the same response.

People aged 15-29 made up more than 40% of total migration within Japan last year, reflecting the fact that people move more when they are young for college or to find work.

As women create new realities for themselves, society will have to adjust.

"Companies in rural areas should target young people in their 20s who have yet to decide on their life events, their jobs, marriage, accepting promotions," said Kanako Amano, research fellow at NLI Research Institute. "Businesses need to change their male-oriented ways of working and thinking. They should consider hiring women if men and women are similarly qualified."

Some local governments have been able to adjust. "Many municipalities that saw increases in the number of young people are commuter towns that have increased their support for families raising children," Amano said.

But others are struggling to come up with effective measures.

Aichi in 2018 asked 18- to 39-year-old women from the prefecture why they moved to Greater Tokyo. Many said they moved to the capital area because they wanted to keep working and moving up the career ladder after getting married and having children.

Many respondents also said Greater Tokyo offers more suitable opportunities than can be found in rural areas.

Aichi has urged business owners to hire more women and change their mentality. It has also distributed leaflets that stress the prefecture's livability at Tokyo universities and other locations. But these efforts have yet to bear fruit.

But the trend is not necessarily good for Tokyo. Overcrowding has become a problem in the metropolis. As of last October, the capital was the only prefecture in Japan that saw a year-on-year increase in the number of children, according to the Ministry of Internal Affairs and Communications. There are still many children on nursery school waiting lists, and elementary schools in central Tokyo do not have the capacity to accommodate the increasing numbers of children.