Mini ecig kits are sold on TV Shopping and can be bought online. I bought my very first ecigs online here in Japan. As far as I can tell, nicotine eliquid is not readily available, so I buy all my stuff from China, the US and the UK. I have never hasd any problem at all even though my parcels were sometimes inspected (I could see by the 'inspection' tape) but nothing was said or removed even though huge amounts of liquid comes at a time.
I have flown in out out of Japan with lots of ecig supplies and was even asked once or twice what it was, since it's all together in a bag and kind of obvious, but once I explained and took a puff, they seemed facinated and very interested, then smiled and waved me through. Other times my stuff was seen but no comments were made. Politeness with all officials is very important...
I have also vaped both at Narita and Hanada. Not TOO blatently, but not exactly sneakily either. I often have my ecigs on a lanyard and take puffs wherever I feel like it.... I also vape in shops, at the station, in resturants in the non smoking section (where I line up a few of my PV's in full view) and recently been
vaping my HUGE Provari and Map Tank openly in shops etc. and in front of the Police. Absolutely no-one says anything.
Hope this helps?
I just remembered!!! It must be 'legal' as you put it, since Totally Wicked UK has opened up an online shop here just a few weeks ago. Now there is NO way they would do something like that if it was illegal.