I don't think it's hard to find people that will ship anywhere, it's just that most people stick to domestic to avoid some risk. You probably won't have Japanese domestic sellers.
LSD is odorless paper, you'll have no problem getting that buying internationally. Australia supposedly has the worst (most effective) customs but I got shroom powder through internationally, risky though. You could get spore prints for shrooms and grow your own.
Do you have a Japanese friend you can ship to? (assuming you are a visitor) I think that foreign looking names on mail get much greater scrutiny. Aside from that LSD should be very safe, as long as you order from the US and not somewhere stupid like the Netherlands.
>>4811 >>4812 The laws are really strict but there to the point where growing/smoking are basically the same thing. At least this is what I was told in the early 2000s. Lots of regular posters on overgrow were from Japan. They had an entire forum dedicated to the county and those guys had some amazing stealth grows doing high yields. I imagine most cannabis you can buy in country was grown on the island indoors. Probably why price and quality vary so much.