They are very strict here for Drugs and Visa and they could be a Headache
when you need to prove that the Liquid is just a Liquid!
But it is not illegal here and you are allowed to carry a "One Month Supply" with you
(Law 2012 and i don't know if they changed it in 2013)
When you are a Super-Serous Person or travel with your Family you should
ask at the Japanese Embassy, who may don't even know E-Cigarettes!
I just used ANA for OBon and vaporized the whole Time and had no problem at all.