Thread:Oppaichan/@comment-5975474-20150604013903

I came from a culture where people address each other by their first name, never use last name in most cases (of course, I would not address my mother by her name, as it is considered to be very RUDE). I've been watching To Love-Ru for some times, and I still feel confused about how people in the series address each other.

As far as I know, when people in JPese address each other by their first name, it is implied that their relationship is somewhat close. But Rito addresses Haruna by her last name, but he calls Run/Ren, Momo or Nana by their first name (Run/Ren is not as close to Rito as Momo/Nana), and this somewhat makes me confused.

If you know much about JPese culture, can you explain me how people in Japan address each other? When will they use last name (surname) or first name? 