Prescription drug question
 

hi all i'm currently living in the US and intend to do a study abroad program in japan. I don't really have much info on what i'm doing school wise or where exactly i'm staying (somewhere right outside of Tokyo) but i had a question that might be a rule infraction to this forum but here it goes.
No matter how much i search the internet i cant get a straight forward answer. i take a small amount of a substance called kratom a couple nights a week to help with my sleep disorder (only thing that has consistently helped with no side effects) SO i was wondering if one of you nice japan folk could find out the legal status of this herb for me. its legal pretty much everywhere accept for Australia and SE Asia. but i know how strict Japanese drug laws are, so i thought better safe than sorry and i should check this out as thoroughly as possible. im leaving middle of July, any information would really help me out.....domo arigato.