Fukushima nuclear accident independent investigation commission by the National Diet of Japan

After the Fukushima nuclear accident, Independent Investigation Commission (IIC) was firstly established in constitutional government by the National Diet of Japan. This article described recognition of its necessity, its setup process, its framework with start from almost zero and about 6 months period and time, its basic way to proceed investigation and several obstacles and hardships, significance of openness to the public, web's communication and simultaneous interpretation (transparency) and basic philosophy of the report. Further significance of Diet's IIC in the democratic system and evaluation of the report were added. As a problem of separation of three powers in Japan, specific recommendations to the legislation of IIC and their future evaluation, nation's governance system problem and social responsibility of scientists and others were also discussed. If Japan were not to be changed after the disaster, Japanese future might be unreliable. (T. Tanaka)