The Tokyo Subway Sarin Attack

A coordinated attack during rush hour

Shortly after 8 a.m. on March 20, 1995, five Aum Shinrikyo members boarded trains on the Hibiya, Chiyoda and Marunouchi subway lines. Each carried packets containing liquid sarin, a highly toxic nerve agent. They punctured the packets inside train cars before leaving the subway system, allowing the chemical to spread among commuters and station staff.

The selected trains passed through or toward Kasumigaseki, the central Tokyo district where major ministries and government offices are concentrated. Victims collapsed on trains, platforms and streets as emergency responders attempted to understand an initially mysterious mass-casualty event.

The human toll

Japanese authorities documented thousands of victims. The Public Security Intelligence Agency later described 13 deaths and more than 5,800 injured people under the victim-benefit system then in use. A woman who had remained severely disabled after exposure died in March 2020; later commemorations and Japanese news reports therefore count 14 people killed and more than 6,000 injured.

Survivors have reported long-term physical effects, eye and neurological problems, post-traumatic stress and persistent anxiety. Families of those killed and seriously injured have continued to participate in memorials at Kasumigaseki Station and elsewhere.

Why investigators focused on Aum Shinrikyo

The attack did not emerge in isolation. Before March 1995, investigators and journalists had already linked suspicious chemical activity near Aum facilities to an earlier sarin attack in Matsumoto, Nagano Prefecture, in June 1994. The cult had also been connected to abductions, violent attacks and efforts to obtain or manufacture dangerous weapons.

Japanese authorities launched large-scale searches of Aum facilities after the subway attack. Investigators uncovered evidence of chemical-weapons production and a wider pattern of criminal activity. Chizuo Matsumoto, the cult leader better known as Shoko Asahara, was arrested in May 1995.

The criminal cases

The subway attack became part of a much larger set of prosecutions involving Aum members. Japan's Ministry of Justice reported that 189 people were indicted in relation to a series of Aum cases, including the subway sarin attack. The proceedings took years because defendants faced different allegations and because several major cases moved through lengthy appeals.

Asahara was prosecuted not only for the subway attack but also for other killings and violent crimes attributed to the cult. In February 2004, the Tokyo District Court sentenced him to death. His death sentence became final in September 2006 after the Supreme Court rejected a special appeal.

Executors, drivers and planners

The attack required several distinct roles. Five men released sarin on the trains, while other members drove them to or from stations, manufactured the chemical, coordinated logistics or participated in planning. Japanese court proceedings established criminal responsibility across those roles.

Because the Aum prosecutions covered many separate incidents, not every defendant received the same sentence and not every death sentence related only to the subway attack. The correct legal picture is therefore broader than a single "attack trial": a network of cases established responsibility for the subway operation and other Aum crimes.

Final judgments and the 2018 executions

By January 2018, the final remaining major Aum criminal proceedings had concluded. Japanese authorities stated that all criminal trials connected with the series of Aum cases had ended.

Thirteen Aum members had final death sentences for the wider series of serious crimes. Japan carried out seven executions on July 6, 2018, including Asahara, and six more on July 26. The Ministry of Justice's Public Security Intelligence Agency records that all 13 final death sentences were carried out that month.

A continuing public-security legacy

Aum Shinrikyo no longer operates under its original structure, but successor organizations have remained subject to Japanese public-security monitoring. Authorities have repeatedly emphasized that the history of the subway attack remains relevant because successor groups continue to recruit and maintain ideological connections to Asahara.

The attack also changed emergency planning, chemical-defense readiness and public understanding of non-state groups capable of acquiring weapons of mass destruction. Thirty-one years later, memorial observances in March 2026 again honored the 14 people killed and the thousands injured.

Timeline

Current status

The Tokyo subway sarin attack is solved and adjudicated. The perpetrators and organizers were identified through extensive criminal proceedings, Asahara and other condemned Aum members were executed in 2018, and the final trials in the broader Aum series had concluded by that year. The long-term medical and psychological consequences for survivors remain part of the case's continuing legacy.