Three former utility firm bosses have been charged with negligence over the Fukushima nuclear disaster - the first ones from the company to face a criminal trial.
A group of court-appointed lawyers have indicted Tsunehisa Katsumata, the then chairman of Tokyo Electric Power Company (TEPCO), along with two other ex-executives. The three men are charged with professional negligence, according to broadcaster NHK.
The indictment follows a decision by an 11-member judicial committee in July to send the three men to criminal court after prosecutors dropped the case.
Three reactors at the Fukushima Dai-ichi plant damaged in the March 2011 earthquake and tsunami suffered meltdowns, triggering massive radiation leaks that forced tens of thousands of people to evacuate.
Experts say it may be difficult to prove criminal responsibility for failing to prevent the Fukushima meltdowns, but many people, including residents affected by the disaster, say they hope that any trial would reveal more facts about the disaster and Tepco's role that the utility has not disclosed.
The committee said in July that the three men neglected to take sufficient measures even though they were aware of the risk of a tsunami at the Fukushima plant.
It said they should be charged with professional negligence resulting in death and injury during the accident and its aftermath, including the deaths of dozens of elderly people in a hospital who died during and after the lengthy evacuation.
Tokyo District Court has since selected a team of five lawyers to act as prosecutors to formally press charges in court.
The government and parliamentary investigative reports have said Tepco's lack of a safety culture and weak risk management, including an underestimate of tsunami threats, led to the disaster. They said Tepco ignored tsunami safety measures amid collusion with then-regulators and lax oversight.
Tepco has said it could have been more proactive on safety measures, but a tsunami of the magnitude that crippled the plant could not be anticipated.
While struggling with a clean-up at the wrecked Fukushima plant that will take decades, Tepco is hoping to restart two reactors at the Kashiwazaki-Kariwa plant in northern Japan.
The disaster resulted in Japan taking all of its nuclear power reactors offline for checks. Of the 43 workable reactors in Japan, three have been put back online since last year, while the remaining are still offline for repairs or safety checks.