KENDO, as it is played today, was developed about two hundred years ago, when the "shinai", a bamboo sword, was devised to enable the safe and free practice of the ancient military art of sword. During the 16th century, when Japan was in the period of successive and nation-wide civil wars, the techniques of sword manipulation were studied as a matter of life and death. Warriors were trained to brandish a sword as though it had been an extended part of their arms. Wooden swords were used more freely to study and practice the art of sword fighting. Eventually basic ways were selected for manipulating a sword to be called "kata", fundamental forms of KENDO.
Under the warring environments there were many expert swordsmen, claiming originality in one way or the other to establish schools of their own, counting in number as many as 600 in history. In the warring days it was, of course, their immediate object to kill their opponents. In doing so, "Bushi" warriors were taught to cause instant death without unnecessary agony to the slain. It was an etiquette in sword fighting.
"Kata" forms have continued to be most important in KENDO to master. But mere combinations of "kata" forms are not sufficient to cover techniques required to meet all happenings in sword fighting. The free practice was then in need to encourage the development of "shinai" bamboo swords and protective gears for safeguard.
Today KENDO followers train themselves primarily by using bamboo swords and learn "kata" forms by using real or wooden swords.