In Japan, people greet each other by bowing.
A bow ranges from a small nod of the head, to a long, 90 degree bend at the waist.
In most traditional martial arts dojo's a seated bow may also be performed from (Seiza) the traditional Japanese Sitting method and the actual angles apply in much the same way.
Bowing is considered extremely important in Japan, so much so that, although children normally begin learning how to bow from a very young age, Japanese companies commonly provide training to their employees in how to execute bows correctly.
Most Westerner's probably won't notice the sophisticated use of the bow in Japanese culture,
the Japanese bow to one another as a greeting, a parting gesture, a way of expressing humility, respect or apology, and an alternative to waving or saying "Hi."
The Japanese often bow every time they meet someone, even if they have already seen that person several times that day. sometimes they even bow to each other while they are riding bicycles.
There are four bows, each with a different meaning:
The first and by far the most informal is the nod-bow, usually performed with about 5 Degrees angle and usually just a small nod of your head, this is generally reserved for close friends,
In the Dojo this bow may be performed by the Master to his students and is by no means regarded as a sign of disrespect, more so a cultural display of etiquette.
The degree of the bow expresses the level of respect towards the other person.
In Japan generally bowing by about 15% is regarded as sufficient – especially for foreigners.
However when bowing to someone of higher social status, a deeper, longer bow indicates respect, a small head nod is casual and informal, most Japanese do not expect foreigners to know proper bowing rules and so a nod of the head is usually sufficient.
Greeting Bow, Eshaku (会釈), 15 Degrees:
In Japan this bow is for greetings, mostly for people you already know or are equals with, the 5 degree bow” above is similar, but for when you know someone a lot better.
In The Dojo this bow is suitable for fellow students.
Respect Bow, Keirei (敬礼), 30 degrees:
This is where bowing gets respectful.
Thirty degrees is actually quite a lot and feels like quite a lot,
This bow is reserved for your Sensei or students with much higher ranks.
Highest Respect Bow, Saikeirei 最敬礼, 45 degrees:
This bow conveys deep respect, gratitude or an apology,
In the Dojo this Bow is only performed to your Master.