— Two weeks ago, Kimie Furuuchi received a letter encouraging her to come home. It was signed by the mayor, and it began, “Dear Minamisoma Evacuee . . .

“We are trying to create the environment where all evacuees can come back to Minamisoma as soon as possible,” the letter read.

Furuuchi folded the letter up and thought it all seemed premature. Government authorities and radiation experts kept saying that her old city could become safer, but almost nobody said it was safe. The ambiguity meant that Furuuchi, like tens of thousands of others who fled their homes after the Fukushima Daiichi nuclear disaster in March, had to weigh the comfort of a homecoming against a danger she could not quantify.

As Japan readies this month to cancel its “evacuation preparation zone” — the ring just beyond the 12.4-mile no-entry radius — the long-term viability of the region depends on people returning to their towns and accepting the new risks. For cities such as Minamisoma, the largest in this ring, the next months will determine whether they wither or endure. That’s why officials here are pushing for people to return, even before they know the outcome of frenzied decontamination efforts.

“We are aiming to make the city safer,” Minamisoma Mayor Katsunobu Sakurai said in an interview. “But we don’t know if it’s safe or not.”

Tokyo wants local governments such as the one in Minamisoma to decontaminate public areas, reopen schools and re-create a region that offers jobs and security. But research offers conflicting data on the long-term effects of low-level radiation, particularly on children and pregnant women.

Furuuchi and her three teenagers have lived since April 3 in Chiba, an hour’s train ride from Tokyo. The oldest two like city life even more than they expected. And when the family visited Minamisoma last month, they agreed that the things they loved about it were gone. Fewer residents played outside. Nobody visited the beach. The main shopping street had become a glum passageway of shuttered storefronts.

But for Furuuchi, Minamisoma also offers one thing that Chiba has not given: a job. The hospital where she worked has been calling; they want her to return. Furuuchi doubts it’s safe to go back, but recently she pulled her kids together and said, “Let’s talk about the best way to decide.”

Seeing an opportunity

In an unlucky region, Minamisoma got lucky. The city center sits about 15 miles northwest of the nuclear plant, and its radiation levels — 0.61 microsieverts per hour Aug. 26 at the city office — are a small fraction of those in towns closer to the plant. The levels are also far below those in many mountainside hot spots farther away. If you spend a year in Minamisoma, you’ll probably get one-fifth to one-fourth of the government’s maximum 20-millisievert annual limit for adults.

In the initial days of the disaster, amid explosions at three of Fukushima Daiichi’s reactors, the government urged those between 12.4 and 18.6 miles from the facility to evacuate or stay indoors. Tokyo modified its orders in late April, removing the request to stay inside, but the area still had a special designation — it was a place where residents should be ready to flee in case the situation worsened.

People fled anyway. Minamisoma, which had a population of 71,000 before the disaster, at one point had lost six of every seven residents.

But with a plan now to cancel the evacuation zone between 12.4 and 18.6 miles, the government sees an opportunity in Minamisoma. The city has recovered 55 percent of its population. If it can regain its school-age population, it can also regain a semblance of normalcy — a key benchmark of progress in efforts to overcome the nuclear disaster.

Efforts to decontaminate have not eliminated uncertainty for residents, especially young families, weighing a return. The local government mapped out a massive decontamination plan, but officials lacked the funding to test it with a scientific trial run, and they can’t say for certain that it will work. City council member Showichi Ogawa said it’s less a matter of eliminating radiation than “learning to live with radiation.” He said people here could be scrubbing rooftops, discarding soil and unplugging tree roots for decades.

On a volunteer basis, Tatsuhiko Kodama, head of the Tokyo University Radioisotope Center, has been spending his weekends in Minamisoma, advising on the cleanup. The city’s challenge, chiefly, is to dispose of cesium-137, a radioactive isotope with a half-life of 30 years. Because cesium sticks to soil, Kodama said, the key is to shave off a layer ofland — and then deposit the contaminated pile somewhere safe.

By the end of September, Minamisoma wants to cut its current radiation levels in half, with the goal of reopening 12 schools by mid-October. Until then, 10 construction companies have been commissioned to bring heavy machinery to playgrounds, lift five centimeters of soil from the top, then bury it roughly one meter below the playground inside a protective bubble, made partly of rubber.

For now, the central government has given Minamisoma enough funding to decontaminate only public areas, not its thousands of homes. Kodama has also suggested that the town improve its monitoring of food contamination, saying food safety is the greatest risk.

Conflicted about the decontamination plan, one local elementary school principal, who spoke on the condition of anonymity to talk candidly, said it was “critical” to reopen the schools soon. But he’s not allowing his children to return.

“Can I say it’s safe?” the principal said. “No, I can’t say that.”

Tied to a job

Furuuchi figures her family is in a lousy spot either way. She does not want to return to Minamisoma. She fears the town is unsafe — or at least will prove to be as the years pass and health problems emerge. But she also feels she must return. She’s on a nine-month leave from her job. If she were to quit, she would have to pay back the tens of thousands of dollars her hospital has paid to subsidize her nursing classes. She does not have the money.

It’s twisted, Furuuchi said, that the nursing classes have her tied. Soon after she divorced, Furuuchi had decided to take the classes to boost her earning power, to gain independence.

The family recently talked about something that months ago seemed unimaginable: Perhaps the oldest children — Mikado, 16, and Tensei, 15 — can stay in Chiba until they finish high school, while Furuuchi and 13-year-old Ren return home. Mikado and Tensei can get better educations in Chiba. They can live nearly for free, with evacuee subsidies. An uncle who lives close by can watch over them.

As her children had dinner one night last month, Furuuchi said the disaster had “turned their lives upside down.”

“But I will go back, I think,” Furuuchi said.

“You can’t quit your job,” Mikado said, nodding.

“I can’t quit my job,” Furuuchi said.

Special correspondent Ayako Mie contributed to this report.