Tokyo subway sarin attack

The Tokyo subway sarin attack (Japanese: 地下鉄サリン事件, Hepburn: Chikatetsu sarin jiken; lit. 'subway sarin incident') was a domestic chemical terrorist attack perpetrated on 20 March 1995, in Tokyo, Japan, by members of the Aum Shinrikyo cult. In five coordinated attacks, the perpetrators released sarin on three lines of the Tokyo Metro (then Teito Rapid Transit Authority) during rush hour, killing 13 people, severely injuring 50 (some of whom later died), and causing temporary vision problems for nearly 1,000 others, a total of 6,300 people were injured. The attack was directed against trains passing through Kasumigaseki and Nagatachō, where the National Diet (Japanese parliament) is headquartered in Tokyo.

The group, led by Shoko Asahara, had already carried out several assassinations and terrorist attacks using sarin, including the Matsumoto sarin attack nine months earlier. They had also produced several other nerve agents, including VX, attempted to produce botulinum toxin and had perpetrated several failed acts of bioterrorism. Asahara had been made aware of a police raid scheduled for 22 March and had planned the Tokyo subway attack in order to hinder police investigations into the cult and perhaps spark the apocalypse the leader of the group had prophesied.

In the raid following the attack, police arrested many senior members of the cult. Police activity continued throughout the summer, and over 200 members were arrested, including Asahara. Thirteen of the senior Aum management, including Asahara himself, were sentenced to death and later executed; many others were given prison sentences up to life. The attack remains the deadliest terrorist incident in Japan as defined by modern standards.

Aum Shinrikyo was founded in 1984 as a yoga and meditation class, initially known as Oumu Shinsen no Kai (オウム神仙の会; "Aum Divine Beings' Society"), by pharmacist Chizuo Matsumoto. The group believed in a doctrine revolving around a syncretic mixture of Indian and Tibetan Buddhism, as well as Christian and Hindu beliefs, especially relating to the Hindu god Shiva. They believed Armageddon to be inevitable in the form of a global war involving the United States and Japan; that non-members were doomed to eternal hell, but could be saved if killed by cult members; and that only members of the cult would survive the apocalypse, and would afterwards build the Kingdom of Shambhala. In 1987, the group rebranded itself and established a New York branch; the following year, it opened a headquarters in Fujinomiya. Around this time, the mental health of Matsumoto (now going by the name Shoko Asahara) deteriorated – he developed a health anxiety and expressed suicidal views. In August 1989, the group was granted official religious corporation status by the Tokyo Metropolitan Government, giving it privileges such as tax breaks and freedom from governmental oversight. This recognition caused dramatic growth, including an increase in net worth from less than 430 million yen to over 100 billion yen (approximately $7m to $1.3b in 2024 dollars) over the next six years, as well as an increase in membership from around 20 members to around 20,000 by 1992. The drastically increasing popularity of the group also saw an increase in violent behavior from its members. In the year preceding its recognition by the Tokyo government, a member of the cult – Terayuki Majima – had accidentally drowned during a ritual; his body was cremated, with the remaining bones ground up and scattered over a nearby lake. Majima's friend – a fellow member of the group – was murdered by members acting under Asahara's orders, after he became disillusioned and tried to leave. Three months after recognition, six Aum Shinrikyo members were involved in the murder of Tsutsumi Sakamoto and his family. Sakamoto had been working on a class-action lawsuit against the cult. Asahara had previously advanced the concept of 'poa': a doctrine which stated that not only were people with bad karma doomed to an eternity in hell (unless they were 'rebirthed' through intervention by 'enlightened people'), but that it was acceptable to kill those at risk of bad karma to save them from hell.

Asahara had experienced delusions of grandeur as early as 1985. In his meditation sessions during this time, he claimed that the god Shiva had been revealed to him, and had appointed him 'Abiraketsu no Mikoto' ('The god of light who leads the armies of the gods'), who was to build the Kingdom of Shambhala, a utopian society made up of those who had developed 'psychic powers'.

In 1990, Asahara announced that the group would run 25 candidates in the election that year to the Japanese Diet, under the banner of Shinrito (真理党, "Truth Party"). Despite showing confidence in their ability to gain seats in the diet, the party received only 1,783 votes; the failure to achieve power legitimately, blamed by Asahara on an external conspiracy propagated by "Freemasons and Jews", caused him to order the cult to produce botulinum and phosgene in order to overthrow the Japanese government. As members became disillusioned with the group (following contact with the outside world made during the election campaign) and defected, an attitude among the remaining members that 'the unenlightened' did not deserve salvation became accepted.

Attempts to stockpile botulinum toxin proved unsuccessful. Seiichi Endo – one of the members tasked with acquiring botulinum toxin – collected soil samples from the Ishikari River, and attempted to produce the toxin using three 10,000-litre (2,600 US gal) capacity fermenters. In total, around 50 batches of 9,000 litres (2,400 US gal) of a crude broth were produced – however, the cult did not attempt to purify the broth (which mostly would have consisted of bacterial cultivation media; one member even fell into one of the fermenters and nearly drowned, but otherwise suffered no ill effects).

Despite mouse bioassays run by Tomomasu Nakagawa (another cult member assisting Endo) returning no toxic effects, in April 1990 the crude broth was loaded into three trucks equipped with custom spray devices, which was to be sprayed at two US naval bases, Narita airport, the Diet building, the Imperial Palace, and the headquarters of a rival religious group.