The Sarin attack on the Tokyo subway, usually referred to in the Japanese media as the Subway Sarin Incident (地下鉄サリン事件, Chikatetsu Sarin Jiken), was an act of domestic terrorism perpetrated by members of Aum Shinrikyo on March 20, 1995.
In five coordinated attacks, the perpetrators released sarin on several lines of the Tokyo Metro, killing thirteen people, severely injuring fifty and causing temporary vision problems for nearly a thousand others. The attack was directed against trains passing through Kasumigaseki and Nagatachō, home to the Japanese government. It is the most serious attack to occur in Japan since the end of World War II.
Aum Shinrikyo is the former name of a controversial group now known as Aleph. The Japanese police initially reported that the attack was the cult's way of hastening an apocalypse. The prosecution said that it was an attempt to bring down the government and install Shoko Asahara, the group's founder, as the "emperor" of Japan. Asahara's defense team claimed that certain senior members of the group independently planned the attack, but their motives for this were left unexplained.
Aum Shinrikyo first began their attacks on June 27, 1994 in Matsumoto, Japan. With the help of a converted refrigerator truck, members of the cult released a cloud of sarin which floated near the homes of judges who were overseeing a lawsuit concerning a real-estate dispute which was predicted to go against the cult. From this one event, 500 people were injured and seven people died.
On Monday March 20, 1995, five members of Aum Shinrikyo launched a chemical attack on the Tokyo Metro, one of the world's busiest commuter transport systems, at the peak of the morning rush hour. The chemical agent used, liquid sarin, was contained in plastic bags which each team then wrapped in newspaper. Each perpetrator carried two packets of sarin totaling approximately 900 millilitres of sarin, except Yasuo Hayashi, who carried three bags. Aum originally planned to spread the sarin as an aerosol but did not follow through with it. A single drop of sarin the size of a pinhead can kill an adult.
Carrying their packets of sarin and umbrellas with sharpened tips, the perpetrators boarded their appointed trains. At prearranged stations, the sarin packets were dropped and punctured several times with the sharpened tip of the umbrellas. The men then got off the train and exited the station to meet his accomplice with a car. By leaving the punctured packets on the floor, the sarin was allowed to leak out into the train car and stations. This sarin affected passengers, subway workers, and those who came into contact with them. Sarin is the most volatile of the nerve agents, which means that it can quickly and easily evaporate from a liquid into a vapor and spread into the environment. People can be exposed to the vapor even if they do not come in contact with the liquid form of sarin. Because it evaporates so quickly, sarin presents an immediate but short-lived threat