Bowing "鞠躬" refers to the action of showing respect, which the user would tuck in their torso and bend at slightly forward til 90 degrees, and back to the original position by putting two palms together.
This clan tradition was created by The Emperor during his earliest speech in the division era "Solemn Tears Era" which believed is an act to show ones' loyalty and respect towards his peers and comrades. This clan tradition remains today as one of the famous and popular act by his soldiers.
"Regardless ranks or title, we musn't forget to give a bow to each other and especially our nearest comrades. Not doing so, is an insult." - Sonicz gave his speech in the general meeting.