Shoko Asahara, 53, was arrested at a commune near Mount Fuji two months after the Aum sect released Nazi-invented sarin gas in rush-hour Tokyo subway trains, killing 12 people and injuring thousands.
Japan, the only major industrial nation other than the United States to use the death penalty, has stepped up the pace of executions recently. It has hanged 15 people so far this year, the highest annual total since 1975.
Asahara, whose real name is Chizuo Matsumoto, was sentenced to death in 2004 by the Tokyo District Court for the gas attack and other crimes.
His lawyers appealed, arguing they could not communicate with the nearly blind Asahara because he only mumbled nonsense, but the former acupuncturist lost his appeal in 2006.
The bearded guru was revered as a god by his Aum Supreme Truth sect, whose hardline followers are under constant surveillance.
His crimes resulted in a total of 27 deaths and several thousand injuries, with many of the victims still suffering serious physical and psychological effects.
Shoko Asahara, 53, was found responsible for gassings on Tokyo rush-hour subways that killed 12 and sickened thousands, and was sentenced to death by the Tokyo court in February 2004 for murder and attempted murder.
The gassings with the lethal nerve gas sarin injured about 5,500 people, some permanently, and stunned the public, shattering Japan’s image as a haven of public safety.
An appeal by Asahara, whose real name is Chizuo Matsumoto, was rejected by Japan’s Supreme Court in September 2006 and he is on death row.
A spokesman for the district court said the petition for retrial had been filed Monday.
The spokesman declined to say how long it would take to make a decision or to comment on other procedural matters, but the Yomiuri newspaper said the government did not usually carry out executions while a retrial petition was being considered.
The newspaper said the petition was based on what Asahara’s lawyers considered new evidence from testimony by a senior member of the cult that the attacks had been carried out against their leader’s wishes.