Hi, I just registered to reply to this thread...

Firstly, there are a lot of smokers in Japan, both native and foreign.
Secondly, it grows wild(!) in the Northern parts. Cops are waiting to bust people who try to pick it though.
Thirdly, growing by yourself is probably the best option. Those of us that do grow, keep it very, very hush-hush. If you are not a total idiot, you have a good chance of not going to Japanese prison.
You can make some very good money selling it, but thats not what I choose to do.

If you're in a big city (ie. Tokyo, Osaka etc) then you shouldn't have any problem getting some weed. Will post some more when I get home...

Edit: I see that you're only here sort-term. Suck it up, son.
If you must, however, find the middle-eastern guys selling jewellery downtown at night.

get caught growing in japan and expect to get kicked out of the country, or go to jail for the rest of your life. i dont recommend it.

5-7 depending on size of grow, deportation immediately after sentence served and 10 years, if not life ban on entering Japan.
Simple possession of any amount: 5 years and the above.

what you should do is find a japanese girl what smokes and try to get some fine japanese ass. then if she trusts you enough to let you put your penis in her, she will trust you enough to sell you pot or introduce you to her dealer and if by chance yous 2 are girls, find some small jap penis

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My grow

All i have to say is watch the show " Locked Up Abroad " and think about it real hard if ya wanna try it ! Good Luck