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 tools are constantly changing, requiring that the techniques to use them be continuously reinvented. The history of Japan is somewhat unusual in its relative isolation. Compared with the rest of the world, the Japanese tools of war evolved slowly. Many people believe that this afforded the warrior class the opportunity to study their weapons with greater depth than other cultures. Nevertheless, the teaching and training of these martial arts did evolve. For example, in the early medieval period, the bow and the spear were emphasized, but during the Tokugawa period, fewer large scale battles took place, and the sword became