In karate we bow for several reasons:
There is a saying in the Japanese Martial arts ‘Rei Ni Hajimari Rei Ni Owaru’. This means that Japanese Martial Arts start and finish with a bow.
This etiquette is an integral part of Budo and without it Budo would be the same as street fighting. Another Budo saying is, ‘the more rice on the stalk the deeper it bows down’ – the more Budo training the more calm, dignified and humble the Karateka becomes. The beginner must practice etiquette in order to make himself or herself a better person.
We show respect to the inventors of the art by bowing to the Shomen side. We bow to our instructor out of respect and we bow to our seniors (Sempais). Our bow expresses our respect to the art and the respect to our training partners. With bowing and lowering our head, we also show that we put our trust in our teacher and trust in his guidance. The bow expresses further that we are willing to listen and to learn (we offer our ears with this move).
Karate is influenced by the Japanese culture and the Samurai code with its rituals – one of them is the bow. The bow in Japanese tradition and the way you bow depends on whom you were bowing to, your personal status within the society, age, gender and so on. You may have to bow longer and deeper to a higher ranked person, an older person or your boss.
The goal is to show respect at many levels!