The criminal trial of three former top executives at Tokyo Electric Power Co. over the triple meltdown at its Fukushima No. 1 nuclear power plant in 2011 has begun at the Tokyo District Court. The point at issue is whether it was possible for the accused to have foreseen the giant tsunami that led to the nuclear disaster and whether they could have taken steps to prevent the catastrophe. Proving the case against them will not be easy. Still, the court and the lawyers acting as prosecutors should leave no stone unturned in their effort to unravel Tepco's decision-making process regarding the nuclear power plant's safety measures. This is critical as a great deal remains shrouded in mystery as to what the power company and its executives did or failed to do to prepare the plant for the kind of disaster that struck it six years ago.

The trial was set after an Inquest of Prosecutions, composed of ordinary citizens, twice overturned the prosecution's decisions not to pursue charges against the former Tepco executives — former chairman Tsunehisa Katsumata, 77, and two ex-vice presidents, Sakae Muto, 67, and Ichiro Takekuro, 71.

Three lawyers, who acted as prosecutors to indict the men in February, charge that the former executives were well aware of the possibility that a tsunami higher than the Tepco plant site, which is 10 meters above sea level, could hit the facility and flood the reactor turbine buildings, resulting in a loss of power that would cause the plant's cooling system to fail. Yet they neglected to take any precautionary measures to prevent such an outcome. Such negligence on the part of the Tepco executives, the lawyers charge, led to the hydrogen explosions at the plant's Nos. 1 and 3 reactors on March 12 and 14, 2011, injuring 13 people at the scene and forcing patients at a nearby hospital to endure long hours of evacuation, which resulted in 44 deaths.