A Japanese court is due to rule next month on a claim that Tokyo Electric Power is responsible for a woman’s suicide, in a landmark case that could force the utility to publicly admit culpability for deaths related to the Fukushima nuclear disaster.

In July 2011, nearly four months after the massive earthquake and tsunami that triggered a series of catastrophic failures at the Fukushima Daiichi nuclear plant, Hamako Watanabe returned to her still-radioactive hilltop home, doused herself in kerosene and set herself on fire.

She left no suicide note, but her husband Mikio says plant operator Tokyo Electric is directly responsible.

“If that accident hadn’t happened, we would have lived a normal, peaceful life” on their family farm some 50 km (30 miles) from the plant, said Watanabe, now 64, who discovered her charred body.

A district court in Fukushima is expected to rule in late August on Watanabe’s lawsuit, which Tokyo Electric (Tepco) is contesting. The outcome could set a precedent for claims against the struggling utility, said Watanabe’s lawyer Tsuguo Hirota.

The triple meltdowns at the plant forced more than 150,000 people from their homes. About a third, including Watanabe, remain in temporary housing.

The utility has settled a number of suicide-related claims through a government dispute resolution system, but declined to say how many or give details on how much it has paid.

Japan has made public 25 disaster-related death cases that were settled through the resolution system, some for more than 16 million yen (£91,633).

Causes of death were not always specified, and include those due to natural causes, such as elderly patients who died in evacuation centres.

A Mainichi report this week said arbitrators were encouraged to automatically halve requested damage to expedite the process.

Tepco said it could not comment on pending cases, including Watanabe’s.

Watanabe has so far declined to settle outside of court and has broken off contact with relatives who urged him to drop his suit.

His oldest son left his job after co-workers harassed him, accusing him of using his mother’s death for personal gain. Watanabe is seeking more than 91.16 million yen in damages.

“No matter what verdict I get in August, I just want my wife to rest in peace,” said Watanabe.

DEEP DEPRESSION

Like her husband, Hamako had grown up in Yamakiya, a rural pocket of farms and rice paddies surrounded by hills inside Kawamata Town. Being forced to leave plunged her into a sudden and deep depression, he said.

“For them to argue that the suicide is not directly related is unforgivable,” Watanabe said.

Hirota, Watanabe’s lawyer, said the verdict could set the stage for others who have experienced losses as a result of the nuclear disaster to take similar legal action.

“For the claimants, it’s not about the money. They want to know what the meaning of their husband’s death was, or why their mother had to perish this way,” he said.

Kazuo Okawa, an Osaka-based lawyer who has spent over three decades representing victims of Minamata disease, a neurological syndrome caused by mercury poisoning from industrial wastewater, said that courts in Japan generally tend to favour companies in liability cases.

Civil suits are uncommon in Japan, where victims are far more likely to skirt arduous court battles and accept settlements.

“There are massive hurdles to go to court in Japan. It takes a long time for court cases to proceed and this discourages many victims … If they felt they had a chance of winning they still might, but that hasn’t always been the case,” Okawa said.

EMOTIONAL DISTRESS

The case also highlights what advocates call a quiet crisis of depression in Japan’s disaster zone, which many say has gone unnoticed in a culture that values stoicism and stigmatizes mental illness.

“Their houses are still there, but they can’t go back,” said Shinichi Niwa, a professor of psychiatry at Fukushima Medical University, who said that displacement contributed to anger, despair and suicide.

Between 2011 and 2013, suicides declined 11 percent across Japan. Suicides in Fukushima had also been decreasing in the years before the disaster, but deaths have ticked up in the past two years.

Since April 2011, there have been more than 1,500 suicides in the prefecture. Authorities have so far ruled 54 of those deaths to be “disaster related”.

Japan’s government has dispatched counsellors, appointed a government minister in charge of suicide prevention and provided funding to local organisations for survivors and evacuees like Watanabe.

Tepco was bailed out with taxpayer funds in 2012 and expects to spend more than $48 billion (£28 billion) in compensation alone, and billions more for a decades-long costly decommission.

The utility currently pays all nuclear evacuees a stipend equal of about $1,000 a month for emotional distress caused by the accident. Tepco also provides compensation to those who lost their jobs and partially pays for the value of their homes depending on the length of their forced evacuation.

Those evacuees living in areas that have no timeline for their return receive payment for the full value of their homes.

The utility remains under pressure to cut costs as plans to restart its remaining nuclear complex in Japan’s northwest have stalled in the face of local opposition. Last month, Tepco rejected a request by residents of Namie - less than 10 km (6 miles) from the destroyed plant - to raise their monthly compensation for mental distress.

LONGING FOR HOME

Watanabe’s house is still in an exclusion zone, where traffic is restricted to former residents and decontamination crews. He now lives alone in prefabricated housing on what used to be a sports field and regularly commutes to maintain the empty home, and the yard where his family used to have barbecues and watch the fireflies blinking under the stars.

After evacuating, Watanabe’s family moved through a series of shelters before finding a small apartment. Then he and Hamako lost their jobs at a local chicken farm when it closed as the public shunned food from Fukushima.

“She worried constantly and kept asking, ‘What will we do next?’ and ‘How can we pay our house loan?’”

In late June 2011, Hamako begged Watanabe to take her home. He agreed to go to their house and spend one last night there, hoping the familiar settings would put her at ease.

On June 30, Hamako cooked in the kitchen while her husband cleared the neck-high brush around the house. After, they sat together by a window with a sweeping view of their property. She seemed happy, Watanabe said. She asked him if they really had to leave the next day.

“She said, ‘Well you can go back, but I want to stay here even if that means living alone. I never want to leave my home.’ I told her, ‘Don’t be stupid, we have to leave together.’”

The next morning, Watanabe resumed clearing brush. In the distance, under the spreading boughs of a tall tree, he noticed a fire. He assumed his wife was burning trash as usual, and continued working.