YUBARI, Japan >> Most young people have already fled this city of empty streets and shuttered schools, whose bankrupt local government collapsed under the twin burdens of debt and demographics that are slowly afflicting the rest of Japan.

Now, Yubari, a former coal-mining town on Japan’s northernmost main island, Hokkaido, is hoping an unlikely savior can reverse its long decline: a 31-year-old rookie mayor who has come to symbolize the struggle confronting young Japanese in the world’s most graying and indebted nation.

“Japan will tread the same path someday,” said Naomichi Suzuki, who a year ago this month became the youngest mayor of the country’s most rapidly aging city. “If we can’t save Yubari, what will it mean for the rest of Japan?”

Indeed, the city’s plight and attempt to fight back — which has become a story line in the national media — could offer a glimpse of Japan’s future.

Japan’s overall population fell by a record quarter-million to 127.8 million last year, hurt by falling birthrates and people departing for other countries. By 2060, the Japanese population is expected to fall by an additional one-third, to as few as 87 million — and 40 percent of those remaining will be more than 65 years old.

Japan’s national debt has not preoccupied the world the way Europe’s has. But after years of government spending to shore up the economy, Japanese public IOU’s have mushroomed to almost $12 trillion — more than twice the size of its economy and the heaviest government debt burden in the world. (Its treasury is able to keep financing that debt load by issuing government bonds because Japan, like the United States, is still a global investment haven.)

But in Yubari, the demographic and fiscal demise is on fast-forward. The city’s population has plunged by 90 percent since its heyday as a coal-mining hub in the 1950s and ’60s. Currently, fewer than 10,500 people live in a geographic area approximately the size of New York City. And of those remaining Yubari residents, nearly half are older than 65.

And unlike the national government, Yubari has already faced its day of reckoning with creditors. Crippled by the closure of its coal mines as Japan moved to petroleum-based fuels and nuclear power, and after a failed bid to revive its tourism economy with subsidies from the central government, Yubari went bankrupt in 2007, owing more than $400 million to holders of its municipal bonds.

Under Japanese law that debt must still be repaid under a bankruptcy reorganization the city will be laboring under for the next 15 years.

The city’s services have been cut to the bone, and the public workforce of about 300 has been cut by half. Yubari’s winter festivals have been canceled, its public bath closed and its six elementary schools consolidated into one. The aftermath of the March 2011 tsunami further hurt local tourism.

Yubari cut back on its snow-clearing, and its treasured art museum collapsed under the weight of the accumulated snow. There was no money to rebuild.

Even the growers of the region’s famed cantaloupe melon, which can sell for almost $100 each, are struggling as a younger generation has left farms behind for better jobs elsewhere. Meanwhile, the handful of companies still here complain of a dearth of workers; all but four of the 20 employees at the Yubari Tsumura pharmaceutical plant commute from outside the city.

“Something needed to be done to stop the bleeding,” said Shizuo Shibata, 77, a retired school district worker who has spent his whole life in Yubari. “But anyone who had prospects is leaving.”

It was into these depths of despair that Suzuki, then a 26-year-old public servant in the city of Tokyo’s social welfare department, was dispatched to Yubari on a yearlong loan from the Tokyo Metropolitan Government.

By all accounts here, he quickly established rapport with the locals, volunteering his free time to help resuscitate the city’s annual film festival and checking in regularly with his elderly neighbors. (Suzuki concedes he had little else to do during the long winter evenings.) At the same time, the city’s younger people came to consider him a generational leader.

Suzuki began to advocate a new way of thinking in Yubari: What if the city could do more to safeguard the most essential public services, while negotiating better terms on its debt repayments with the central government?

He began a door-to-door survey to get a better grasp of how the city’s cuts were affecting living standards. He also pushed for the city to set up regular three-way meetings with the central government and the prefecture of Hokkaido, to discuss Yubari’s debt repayments.

In late 2010, eight months after Suzuki had returned to his old job with the Tokyo government, a group of Yubari locals called on him with a bold request: Come back to the city, and run for mayor.

“We needed a break from the past, and he represented a fresh start.” said Naoya Sawada, 44, an entrepreneur and early supporter of Suzuki who now runs Yubari’s revived film festival. “He’s young and he’s an outsider, but in Yubari, that might be a good thing.”

Still, Suzuki was politically untested and a relative unknown. He seemed to have little hope against the incumbent, Hajime Fujikura, a 70-year-old former auto industry executive, or Yukari Iijima, 46, a former national parliamentarian.

Then something remarkable happened in this country usually dominated by the elderly ranks. Fujikura, hearing of young Suzuki’s intended candidacy, declared he would step aside and settle for a city council seat instead.

Emboldened, Suzuki’s camp unleashed a campaign blitz. Trudging through the heavy snow and flashing his winning smile, Suzuki visited more than 5,000 of the city’s 6,000-odd households, laying down his message: Yubari can be saved. The Tokyo governor, Shintaro Ishihara, flew to Yubari to cheer on his former employee.

A record voter turnout produced a landslide victory for Suzuki over Iijima, who stared dumbfounded into local news cameras. Pensioners turned out in droves to the young mayor’s first policy speech to the city council, some in Suzuki fan T-shirts.

In his first year, Suzuki has moved swiftly, abolishing the post of vice mayor and putting the resultant savings on salary toward medical care for the city’s infants. He is moving to sell off some of the city’s bad investments, like Melon Castle, a liquor brewery that sits abandoned in the Yubari foothills.

“He’s just like a son or grandson to many of us,” said Machiko Yoshikawa, 64, a local retiree. “He is working so hard for Yubari.”

Suzuki has also pushed the central government to shorten Yubari’s debt repayment schedule, a move that would free the city sooner from the budgetary constraints of operating under bankruptcy protection. But with tax revenues also falling in the tough economy, debt revamping would be a tall order.

Chronic lack of funds has also slowed Suzuki’s progress. Postponed, for example, are much-needed fixes to the city’s only public clinic, a crumbling gray building that lost all but 19 of its 170 beds when the city’s finances collapsed.

Municipal workers, meantime, complain in private that Suzuki has so shaken up city hall personnel that its affairs are in disarray. Supporters of the defeated Iijima dominate the city council, blocking proposals and hurling criticism at the young mayor.

Critics cannot deny, though, that Suzuki is making his share of sacrifices for Yubari. He is not only Japan’s youngest mayor, but also thought to be its lowest-paid one. His annual salary of 3.74 million yen (about $46,000) is a third less than what he was making in Tokyo and lower than some first-year salaries there.

He was initially refused a loan to buy his home in a 60-year-old Yubari housing project because his four-year term mayoral term fell short of the five-year stable employment outlook required for new mortgages. And Suzuki and Manami, his wife of 11 months, have registered their marriage at city hall, but are unsure when they can afford a wedding. “Both Yubari and I have a mountain of debt,” Suzuki jokes.

“In many ways, it’s not my generation’s fault that Japan has so much debt,” he said. “But blaming others won’t get us anywhere. We just need to find a way forward. It’s the responsibility of all of us born into this age.”

© 2012 The New York Times Company