Bored, Nepalis (and many other nationalities as well) are required to have transit visas (even when you are only changing flights and do not intend to leave the airport) at many airports (UK and Hong Kong for example) barring some exceptions.

Soju, as far as I know, you do not need a transit visa for Japan.

बिहान बिहान soju सम्झिएर घुटुक्क पानी आयो गाँठे। 

I had once purchased a bottle of Ginseng ju while transiting at Incheon, really good stuff :):)