In the 2015 Tokyo Drone incident (首相官邸無人機落下事件, susyoukandemujinkirakkajiken), a Phantom 2 drone carrying traces of radiation was found on the roof of the Japanese Prime Minister’s Official Residence. It had been controlled by Yasuo Yamamoto, an anti-nuclear protestor from Fukui Prefecture. Yamamoto flew the drone there carrying sand containing cesium from Fukushima prefecture on April 9, but the drone was not discovered until April 22.
This caused substantial embarrassment to the authorities, both for the security breach and for the delayed discovery of the drone. Yamamoto was later given a two-year suspended sentence, and the incident led to wide-reaching changes to regulations on drones in Japan. This along with other incidents led to authorities in Japan becoming much more aware of issues related to drones.
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