The Japanes sign used across the black and white part of the logo mean Ju Jitsu. 

The yin and yang background is a philosophical concept that describes how opposite or contrary forces may actually be complementary and how they may rise to each other as they interrelate to one another. In Martial Arts terms, this means that instead of meeting force with force, Ju Jitsu is aiming to redirect an opponent's strength against themselves by continuously adapting until a satisfactory outcome is reached.