Aum Shinrikyo (currently known as Aleph) is a Japanese cult and terrorist organization. The group was founded by Shoko Asahara in 1984. The group gained international notoriety in 1995, when it carried out the Sarin gas attack on the Tokyo subway.

The name "Aum Shinrikyo" (オウム真理教, Ōmu Shinrikyō^?) derives from the Sanskrit syllable Aum, which represents the universe, followed by Shinrikyo written in kanji, roughly meaning "religion of Truth". In English "Aum Shinrikyo" is usually translated as "Supreme Truth". In January 2000, the organization changed its name to Aleph in reference to the first letter of the Arabic alphabet, Hebrew alphabet and Phoenician alphabets. It changed its logo as well.

In 1995, the group claimed they had over 9,000 members in Japan, and as many as 40,000 worldwide.^{[citation needed]} As of 2009^[update], Aum Shinrikyo/Aleph membership is estimated about 1,650 people (650 priests, 1,000 laities) by the Japanese government. In July 2011, the cult reported its membership as 1,030.^{[citation needed]}

Shoko Asahara (麻原 彰晃, Asahara Shōkō^?), born Chizuo Matsumoto (松本 智津夫, Matsumoto Chizuo^?) on March 2, 1955, is a founder of the Japanese new religious group Aum Shinrikyo. He was convicted of masterminding the 1995 sarin gas attack on the Tokyo subway and several other crimes, for which he was sentenced to death.

Shoko Asahara was born into a large, poor family of tatami mat makers in Japan's Kumamoto Prefecture. Afflicted at birth with infantile glaucoma, he went blind at a young age in his left eye and is only partially sighted in his right. As a child, Asahara was enrolled in a school for the blind. Asahara graduated in 1977 and turned to the study of acupuncture and traditional Chinese medicine, which are traditional careers for the blind in Japan, and married in 1978. In 1981, Asahara was convicted of practicing pharmacy without a license and fined 200,000 yen.

Asahara's religious quest reportedly started at this time, while he was working to support his family. He dedicated his free time to the study of various religious concepts, starting with Chinese astrology and Taoism. Later, Asahara practiced esoteric yoga and Buddhism.