The Tokyo Subway Sarin Attack
On March 20, 1995, members of the Japanese doomsday cult Aum Shinrikyo released sarin nerve agent on five lines of the Tokyo subway system during the morning rush hour, killing thirteen people, severely injuring fifty others, and causing temporary vision damage to nearly a thousand more. Cult members punctured sealed plastic bags of liquid sarin with umbrella tips on crowded train cars before departing at pre-planned stations. The attack was the most deadly use of a chemical weapon in a terrorist attack in history and demonstrated for the first time that a non-state actor could deploy weapons of mass destruction in an urban transit system.
Aum Shinrikyo, led by the partially blind guru Shoko Asahara, had been developing chemical and biological weapons for years in a sophisticated program funded by hundreds of millions of dollars in cult assets. The group had previously deployed sarin in Matsumoto in 1994, killing eight people. Japanese authorities had been investigating the cult but had not acted quickly enough to prevent the Tokyo attack. In the immediate aftermath, police raided Aum facilities across Japan, finding laboratories, precursor chemicals, and evidence of the group's weapons programs.
Shoko Asahara and senior cult leaders were arrested, tried, and ultimately executed. Asahara and six other senior members were hanged in July 2018 following the conclusion of all appeals in proceedings that had lasted over two decades. Additional cult members were executed subsequently. The prosecutions were exhaustive and the convictions comprehensive, though the drawn-out process — twenty-three years from attack to execution — was criticized by victims and their families.
The Tokyo subway attack transformed global counter-terrorism doctrine by demonstrating the operational viability of chemical weapons terrorism in civilian infrastructure. Transit systems worldwide implemented chemical detection systems; emergency response protocols were redesigned; and intelligence agencies redoubled efforts to monitor groups with the means and motivation to acquire weapons of mass destruction. Japan established new legislation targeting destructive cults. Aum Shinrikyo reconstituted itself under a new name and continued operating as a legal organization in Japan, a source of persistent controversy.