In the early to mid 1990's, Aum Shinrikyo, a group based on the belief of impending Armageddon, used an arsenal of chemical and biological weapons against innocent civilians in a housing complex in Matsumoto and on five subway lines in Tokyo. Prior to the sarin attack in 1995, many Japanese took comfort in their perceived isolation from the high crime rates and corruption of other highly developed countries. The historical and cultural reluctance among officials to prepare for or even discuss terrorism was reflected in underdeveloped consequence management capabilities, which hindered the response effort in both sarin attacks. In the subway sarin attack, the Tokyo metropolitan government assumed the responsibilities of implementing disaster response. In the subway attack scenario, neither the identity of the agent nor the effectiveness of the dispersal methods were known to most victims or emergency response personnel until several hours after the attack. This type of attack was unprecedented, the multi-site nature of the attack was unknown initially, no contingency plans were available on how to respond to a weapons of mass destruction (WMD) attack, and bureaucratic barriers hindered the immediate recognition and response. Subsequent revisions to Japanese incident management are creating response plans, bridging interagency divides, and clarifying chain of command. Problems encountered include underdeveloped communications systems, personal protection and decontamination, medical surge capacity, law enforcement limitations, compensation for damages, and psychological recovery. It is essential that emergency responders in State and local government be prepared to deal with an unannounced attack with a WMD. National-level coordination is vital to ensure that training and equipment are provided to localities in accordance with their needs, and exercises are carried out that involve personnel from multiple agencies and levels of government. Responders from all relevant agencies and all levels of government must practice skills in simulations that involve all aspects of response. 141 footnotes