I just finished researching this for my boss.

OP, whether or not you are allowed to bring into Japan the specific drugs in the specific quantities you want is a question that you need to take seriously. Forgive the alarm, but Japanese authorities can detain you for attempting to bring in even the smallest quantities of prohibited medicines without the proper authorizations. They take the importation of medicines very seriously. Some people report having no trouble at all or not even being thoroughly checked; other people have reported vacation-runining detentions at the airport.

What you need to do first is read this document:

http://www.mhlw.go.jp/english/policy...als/dl/qa1.pdf

It tell you most of what you need to know, as well as what to do to obtain the proper authorization. Also try Googling "Yakkan Shoumei" (the name of the authorization document required under certain conditions).

It may very well be the case that some on FT have entered Japan with certain kinds of anti-anxiety meds with no problems, and it may be the case that entering Japan with a single Xanax pill is no big deal at all...but given the possible consequences involved, I think it behooves you to do your own due diligence.