Hopefully someone can help me out because I am a bit confused. From my understanding, it is very important to declare prescription medicine in Japan (especially narcotics). Does this need to be done before arriving, or at the airport? From what I can gather, they issue a special form that needs to be carried through the duration of stay stating that it is OK to be in possession of the medications. Anyone have experience with this? I will be going soon and don't want to take chances. Thanks.

I live in Tokyo half the year and have never declared any medicine on entry in my 25 years here. The chances of customs searching your luggage are very small. I have had my luggage checked a few times but the customs officer didn't seem to be looking for little things. I give you a 98% chance of not being searched and, if you are, a 98% chance of not having your medicine looked through. Your decision.

http://www.mhlw.go.jp/english/policy/health-medical/pharmaceuticals/01.html

No expertise but unless the medication is a bit high risk (narcotics etc) there seems to be little or no problem for supplies up to a month. Other threads suggest that generally there is not much problem crossing borders if the medicine amounts are reasonable and properly packaged/labeled.

If worried perhaps carry a doctors letter but I have to admit I have travelled to many countries over the years with prescription medication and never questioned.

Some of the dubious origin blue or green tablets widely available in Bangkok might raise a few eyebrows especially without pharmacy labels!

Thanks guys. They are indeed narcotics and I got in touch with Japans Narcotic Control Department yesterday. When bringing Narcotics into the country, no matter the amount, you need pre-approval. In practice, I am sure this is not always followed. But they have very strict prescription medication laws, just like in the US. I was told I need to fill out a form and get a Dr.s note, send it to them and they will send me a certified letter allowing me to carry narcotics while in Japan. Without the letter, you can be arrested on the spot if you are found with them......just like in the US.