As Japan readies for the 20th anniversary this week of the deadly terrorist attack perpetrated by doomsday cult Aum Shinrikyo on Tokyo's subway system, a number of those who fought the cult in its heyday gathered Saturday to reflect on their missteps in handling the crisis — and renew their vow to prevent a recurrence.

Friday will mark the 20th anniversary of the attack, in which Aum members controlled by guru Shoko Asahara, whose real name is Chizuo Matsumoto, sprayed deadly sarin nerve gas on several lines of the Tokyo subway system in March 1995. The unprecedented attack killed 13 and injured more than 6,000.

Hosted by victims' families and anti-Aum lawyers, Saturday's symposium in Tokyo invited professionals from the judiciary, law enforcement and the media to review their approaches to the attack as panelists at the gathering.