Japan has one of the lowest drug abuse and crime rates of any industrialised nation. It also has some of the stiffest laws. After the Second World War it faced an epidemic of amphetamine use and in the early 1960s problems with heroin. A combination of strong law enforcement, stigmatisation of drug users and rehabilitation was successful in overcoming these problems.
After the Second World War Japan’s military stocks of amphetamines went astray, abuse started among artists, musicians, ‘bohemians’ and prostitutes but quickly spread. Not enough was done initially to combat this and it soon escalated.
In 1954, 2 million of the population of 100 million was using tablets. but the epidemic was ended by the enforcement of strict laws. Possession incurred a sentence of 3-6 months: 1 to 3 years was the sentence for pushing and 5 years for illicit manufacture. Convicts were closely monitored on release and immediate restrictions imposed on anyone who relapsed. 55600 arrests were made in 1954 but by 1958 this had dropped to 271 and the epidemic was over.
Measures had been taken against 15% of intravenous users and it seems others were discouraged by fear of arrest. This policy was carried out with broad political consensus and massive public support.

References
1. A Brief Account of Drug Abuse and Countermeasures in Japan Pharmaceutical Affairs Bureau, Ministry of Health and Welfare. Japan. 1972
Masaaki Kato. “An epidemiological analysis of the fluctuation of drug dependence in Japan”, The international Journal of Addictions. 4 (4). Dec. 1969
2. Bejerot N. ‘Drogue et Societe. Masson, Paris 1990. ‘Cannabis: Physiopathology. Epidemiology, Detection.’ Nahas G & Latour C (eds). CRC Press. 1993.