More from Musashi MSK that is of interest....
In tandem with the evolution of the form of the sword, there was a remarkable surge in the development of sword technique. However, dependable documents on schools of sportsmanship did not go back beyond the end of the 14th century. Despite the fact that most schools like to claim that their roots go back to the, kora. (1185 -- 1333) or still further back, the linage of the main traditional schools of the sword can be traced with certainty only back to the middle of the 15th century.
From the last third of the 15th century until the end of the 16th, Japan was the scene of continual warfare among the feudal lords. It was through experience on the battlefield that the sword masters of that period developed their sword technique as well as their basic attitudes toward swordsmanship. The techniques of that period were relatively simple but forceful, since armor was worn in battle. Combatants used existing techniques but also carried on their own personal search for more effective ones, based on their own experience.
While continuing to accept the idea that the true ability to fight comes from actual battlefield experience, some warriors began to attach importance to training, daily preparation for combat. This included matches that often took place without armor, which resulted in the development of greater subtlety in technique.
The practice exercises, kumitachi or tachi uchi, consisted in reproducing combat techniques derived from the experience of various masters. These exercises, in which either a real or wooden sword was used, became standardized