Meeting Etiquette
Greetings in Japan are very formal and ritualized.
It is important to show the correct amount of respect and deference to someone based upon their status relative to your own.
If at all possible, wait to be introduced.
It can be seen as impolite to introduce yourself, even in a large gathering.
While foreigners are expected to shake hands, the traditional form of greeting is the bow. How far you bow depends upon your relationship to the other person as well as the situation. The deeper you bow, the more respect you show.
A foreign visitor ('gaijin') may bow the head slightly, since no one expects foreigners to generally understand the subtle nuances of bowing.