Cannabis and Mushrooms in Japan

Why does Japan have some of the most lenient laws in sexuality and such but a graveyard in soft drugs. Mushrooms were recently banned less than 2 years ago, but ganja prohibition has been around since WWII. I guess the US is to blame for this since it was widely used before the end of WWII. It would almost seem that cannabis would be apart of the Zen culture as it aides quite well in meditation. Mushrooms seem more shamanic but I would see how it easily goes with shinto and the Kami spirits of the forest.

Is there any sign that Japan will open the door on civil liberties in this area? Afterall without mushrooms there would be no Mario, lol. And how deeply has ganja and shrooms been used in spiritual activities in Japan?

-Zen and the artificial meditation
It is just an Americanized Zen starting from around the Vietnam war. I heard it was more LSD-related then, though.

-Civil liberty
It is highly unlikely that a barbarian can enter or get the visa for studying/working to the civilized country like your country if you have a criminal (civilized as you may say) hempish record. This is one of the reasons why I prefer my barbarity against any forms of illegal drugs.