Bowing down in chinese culture?

my geography teacher told me that in certain parts of asia shaking hands is not what they do but rather bowing yet he did not go specifically into that domain since he is from the asion areas. one of my friends went to japan and she told me that in some occasions you might have to bow as a sign ofrgesture if the other person bows,if not then shake hands.it is all about the culture and how it has evolved.bowing means respect,nice to meet you, a greeting sort of per say and from what i have heard to some extent the asian influence transmits its influence onto the japanese to a certain extent which when you visit you will see the difference in cultures and lifestyles because all we do right now is ume.