In stark contrast to America, Japan was not a country well versed in terrorism. It wasn't so much that they were naive, they just didn't have time to think about these kinds of things; Japan was, after all, the only country in the world where "death by overwork" is a recognized and alarmingly common medial term. This is, perhaps, why so many weren't prepared for the events of Day Zero, the long awaited hour of biblical reckoning that was the end goal of Aum Shinrikyo.
Aum was a doomsday cult, one of the biggest in Japan, as well as the most wealthy, despite the 99% of its members who lived in squalor. At it's head was Shoko Aasahara, an imposing, portly man in purple pyjamas and a seemingly always neutral expression. People knew Asahara as the funny looking man who'd come on talk shows to talk about kundalini lines, and they knew the Aum as a bunch of delirious but devoted worshippers who'd often be seen wearing electrode caps. Behind the comical veneer was a horrifying mix of anti-Semitic conspiracy theories, deranged psychological torture, mass murder, drugs and, most importantly, a stockpile of increasingly dangerous chemical weapons. Asahara, who believed himself to be the reincarnation of Jesus, Buddah, Shiva and whatever other mystical being he had decided on during his regular acid trips, had a vision of the end of the world, one that his cult was supposed to survive. Very quickly, that morphed into a doomsday his cult was supposed to bring about, and Aasahara had the money to make that happen; in addition to training select members in military combat, Aum began purchasing things like a derelict gun factory, a discounted military helicopter from the USSR, even whispers of enough plutonium to produce a dirty bomb, if the guru so chose. The end result, much like his belief system, would be a crude mashup of all the ideas Asahara had to bring about the end times, with disastrous results.
As people clogged the streets to get to work on the morning of March 20th, 1995, a lone helicopter suddenly appeared on the horizon, quickly approaching. By the time people started realising something was wrong, the helicopter released the first of several plumes of white mist onto the crowds below. They were the first of many to be struck by a sarin gas attack. As the streets clogged in a panic of either screaming or quickly dying innocents, the Soldiers of White Love, Asahara's hand-picked group of toughs, added to the chaos by beating random passers-by with clubs, smashing store front windows, throwing smoke bombs and marching towards the Japanese National Diet building. With proper protective wear and injections of sarin antidote, the Soldiers were virtually unopposed on their march as police either tried to coral the panic or succumb to the effects of the sarin.
While the casualties skyrocketed in the first minutes, the flaws in the plan quickly bore fruit. The Diet building was quickly evacuated as soon as word reached them of the chaos and death outside. If the Soldiers of White Love even made it inside the building, the would have found it vacant. Tokyo police did their best to corral victims away from other uncontaminated civilians, and emergency triages were quickly set up. Despite not knowing what was actually happening, a former military doctor delayed on his morning commute quickly identified the frothing at the mouth and mass vomiting before death as symptoms of Sarin. Two helicopters belonging to the Police Aviation Unit were launched to chase the Aum helicopter, until a Japan Ground Self-Defense Force Bell AH-1 Cobra shot it down, sending it spiralling into a thankfully vacant stretch of Yoyogi Park.
As with the terror from above, law enforcement seemed to have taken care of the Soldiers of White Love. Despite forming an offensive ring around the Diet building, police soon found the cultists were dropping even before they were hit with clubs. The reasons varied, but all of the soldiers were suffering from a combination of malnutrition and what was reported to be extremely potent amounts of LSD running through their system. Some became vacant and wondered away, others thrashed and screamed like wild animals about the devil coming to eat them for "failing the great guru".
The guru himself was quickly discovered in a secret compartment within his own Mount Fuji compound. Recovered plans seem to suggest Asahara would be escorted into Chiyoda once the soldiers had 'secured' the abandoned building, and would have been proclaimed "Holy Monk Emperor" in order to lead Japan into a war with what he referred to as the "Zionist States of America". Other compounds littered the country, and all were subsequently raided, each producing new numbers of emaciated devotees of the Aum Supreme Truth. Components for a nuclear of dirty bomb were never actually seized during the raids, despite the popular myth among Japanese youths that Aum was planning to blow up Times Square.
