Bowing represents humility. You elevate, honor, and respect the
other person by humbling or lowering yourself. The lower you bow,
the more you are honoring or respecting the other party. A bow should
always be returned. To not bow in return is similar to refusing
a handshake.
The person of lower status usually initiates the bow, bows the lowest,
and is the last one to rise. The most frequent bow is a rather informal
bow of about 15 degrees and is held for one or two seconds. A deeper
bow is used for a superior or for a formal occasion as in the case
of greeting a black belt. It is usually about 30 degrees and is
held for about three seconds. Men usually leave their hands at their
sides while bowing, but women usually place them together on their
thighs with their fingertips overlapping or touching. Heels should
be together. If you rise from your bow and the other person hasn't
risen yet, you should bow again.