Traditional japanese dating customs
Blowing your nose in public is seen as not only rude, but simply disgusting.
Instead people will generally sniffle until they find somewhere private.
This was unthinkable up to the 1950's, but liberal laws in the '60's and '70's have changed all that.
Be polite, follow the "ladies first" rule and brush up on your basic Japanese table manners before going out.
Remember, proper dating etiquette is going to depend a lot on the age, gender and cultural awareness of your date.
Japan has a surprisingly high number of sexless married couples by Western standards. Marriages arranged by the family or friends (such as o-miai) are not unusual in Japan.
Couples rarely live together before marriage, and the Japanese never have children without getting married first (unless it's an accident), because the Japanese law still does not recognise fathers of children born outside wedlock. In other words, the law and one's family pushes people to get married, even if the family has to resort to an arranged marriage, but they won't let them divorce afterwards, even if things don't work out.
Elevator labels will often be missing a fourth floor — and in extreme cases, they will not have floors 40 to 49. 49 is especially unlucky, as it sounds similar to the phrase that means "pain until death." The practice of avoiding No.