The cult carried out five coordinated attacks, releasing the deadly poison gas sarin on three lines of the Tokyo Metro during rush hour.
The BBC explained that it took such a long time for Asahara's execution to take place because in Japan, no one may be executed until every accused person and accomplice has been tried, had their appeals heard, and been sentenced.
Over the years, the group managed to lure in followers from some of Japan's top universities and boasted some 10,000 followers in Japan and another 30,000 in Russian Federation.
Even so, Friday's execution of the seven death row inmates reflected the Justice Ministry's sensitivity not only to the feelings of victims and their families, but a strong public resentment against the deadly crimes perpetrated by him.
Kamikawa announced the deaths on Friday at a press conference, saying, "These crimes. plunged people not only in Japan but in other countries as well into deadly fear and shook society to its core".
The former leader of Aum Shinrikyo, a doomsday cult that killed 13 people in a 1995 sarin gas attack on the Tokyo subway, has been executed, Japanese media report.
The Aum cult was a clear danger to not only to Japan but also to the United States, a 1995 report by a U.S. Senate subcommittee concluded.
The cult also carried out other crimes that together with the subway attack killed 27 people in total. The death toll makes it the worst terror attack in Japanese history, according to The Guardian. It continues to exist, but in a much diminished form.
At Aum's peak in 1995, the number of members exceeded 10,000, but now only about 1,650 members belong to the groups that originated from Aum. Her daughter was killed in the 1995 subway attack.
The images of bodies, many in business suits, sprawled across subway platforms stunned Japan, and triggered public safety steps such as the removal of non-transparent rubbish bins that remain in force to this day. Asahara was executed at a Tokyo detention center, while the others were hanged at the same detention center as well as those in Osaka, Hiroshima and Fukuoka. Sarin, a nerve gas, was originally developed by the Nazis.
The cult began as a spiritual group mixing Hindu and Buddhist beliefs, later including elements of apocalyptic Christian prophesies.
It renamed itself Aleph in 2000 and two splinter groups have been formed, including one established by high-profile former member Fumihiro Joyu.
Kimiaki Nishida, a professor of social psychology at Rissho University in Tokyo, told the Post that "Asahara was talented at brainwashing".
Yuji Ogawara, who heads a lawyers' group against the death penalty at the Japan Federation of Bar Associations, said the executions do not bring closure to Aum's crimes.
Amnesty International said today that executions "do not deliver justice."
"The attacks carried out by Aum were despicable and those responsible deserve to be punished".