Some people believe that it all started when the famous waterman Hamana Kalili lost all his middle fingers. People would wave their hands hiding their middle fingers too for showing respect to him.

Some other people believe that it is just a way of representing a wave breaking on the reef.

Another idea is that it symbolizes the act of drinking something and was introduced by the Spanish while they landed the Hawaiian islands.

However the most extended theory is that it comes from hand position that sailors and Polynesian explorers used to get orientation by the stars while sailing the sea.