You are banned from entering Japan, and there is almost no chance that you will be able to enter the country soon. In Japan, the use and possession of marijuana are prohibited, and Article 5 of the Immigration Control Act states that "a person who has been convicted of a violation of any law or regulation of Japan or of any other country relating to the control of narcotics, marijuana, opium, stimulant drugs or psychotropic drugs, and has been sentenced to a punishment will not be granted landing permission”, meaning that they will not be able to enter the country. There is no deadline set, so they will be unable to enter the country forever. Exceptional cases include those who have a wife or child of Japanese nationality in Japan, but even in such cases, there have been cases where violators who have spent a considerable period of time (such as 10 years) overseas as good citizens have been able to enter the country, especially after their regular employment, income, assets, etc. have been examined by the immigration authorities. Other exceptions include the case of famous musicians being able to enter the country.
