According to the World Drug Report 2011, trafficking and smuggling of marijuana into Japan was decreasing but the production of domestic marijuana was increasing.
In 2009, authorities in Japan seized 207 kilograms of cannabis compared to the 504 kilograms that was seized in 2007.
The arrests of individuals involved in growing marijuana within Japan increased to 243 in 2009, compared to 207 in 2008. In addition, the number of arrests for marijuana smuggling in Japan was 48 in 2009, compared to 85 in 2008.
Source: United Nations Office on Drugs and Crime, “World Drug Report 2011,” June 2011, page 196.