The wai is the common form of greeting and adheres to strict rules of protocol.
Raising both hands, palms joined with the fingers pointing upwards as if in prayer, lightly touching the body somewhere between the chest and the forehead, is the standard form.
The wai is both a sign of respect as well as a greeting. Respect and courtesy are demonstrated by the height at which the hands are held and how low the head comes down to meet the thumbs of both hands.
The wai may be made while sitting, walking, or standing.
The person who is junior in age or status is the first one to offer the wai.
The senior person returns the wai, generally with their hands raised to somewhere around their chest.
If a junior person is standing and wants to wai a senior person who is seated, the junior person will stoop or bow their head while making the wai.
If there is a great social distance between two people, the wai will not be returned.