The main policy research arm of the Defense Agency in 1981 studied the possibility of Japan going nuclear but concluded the idea wasn't feasible in light of the nation's industrial and technological infrastructure, according to a research report obtained by Kyodo News.
The report was compiled by members of the then National Defense College amid the growing threat of the Soviet Union in the early 1980s.
It said Japan was capable of building simple atomic bombs but would require full and active support from the United States in developing payload-capable vehicles and other equipment for tactical and theater nuclear weapons.