Black belt (martial arts) of ability when using these tactics and are sometimes referred to as McDojos or belt factories. In some Japanese schools, after obtaining a black belt the student also begins to instruct, and may be referred to as a senpai (senior student) or sensei (teacher). In others, a black belt student should not be called sensei until they are sandan (third degree black belt), or the titles kyosa or sabom in Korean martial arts as second degree or higher, as this denotes a greater degree of experience and a sensei must have this and grasp of what is involved in teaching
Japanese martial arts first joining with the motion of the opponent (the physical aspect) as well as the intent (the mental portion), then overcoming the will of the opponent, redirecting their motion and intent. Historically, this principle was used for destructive purposes; to seize an advantage and kill one's opponent. The modern art of aikido is founded upon the principle that the control of the opponent achieved by the successful application of "aiki" may be used to defeat one's opponent without harming them. "Kokoro" (心:こころ) is a concept that crosses through many martial arts, but has no single discrete meaning. Literally translating as