Japan was an opium empire that promoted poppy cultivation and sold opium to China via the Korean Peninsula and Manchuria (northern China) before 1945. The GHQ’s occupation policy was firstly based on Japan’s “opium problem” during the war, and incidentally included a policy to regulate marijuana cultivation. The Japanese petitions for permission to cultivate marijuana were consistently rejected by the narcotics officers dispatched from the U.S. Federal Bureau of Narcotics and the Public Health and Welfare Bureau. The Japanese government’s post-occupation policy, which was based on a lack of supplies, led to the intervention of the Natural Resources Administration and the Bureau of Economic Science, and as a compromise, the cultivation of marijuana continued. The General Staff Office was also concerned about the shortage of supplies, and GHQ’s occupation policy was not monolithic. The more smokers became strict nonsmokers after quitting, the more the Japanese Ministry of Health and Welfare’s Pharmaceutical Affairs Division, which had led the cultivation and sale of opium, steered the crackdown to include marijuana, and the direction of strict regulation and punishment has continued to the present day.