Noting the devastating effects of opium on China, the Japanese government during the Meiji Restoration (1868-1912) pursued a vigorous anti-drug policy.
Increased Western influence in the Taisho period (1912-1926) may have contributed to wider acceptance of recreational drug use, yet fewer than 100 narcotics arrests/year were recorded.
During the Showa period (1926-) the number of narcotics arrests increased slightly, then fell. In 1938, 3,600 of Japan’s 70 million inhabitants were known drug addicts.
During WWII, Japan’s isolation, strict anti-drug laws and negative public opinion resulted in a relatively low rate of drug addiction.
Source: Drug abuse and anti-drug policy in Japan. Brit J Criminology 1995; 35:4:491