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 “Kenjutsu” or sword fighting. During the 16th century, when Japan was in the period of successive and nationwide 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 was an extended part of their body. 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", which are the fundamental forms practiced today in Kendo.
Under the warring environments there were many expert swordsmen, claiming originality in one way or the other to establish schools of their own, totalling in number as many as 600 at its peak in history. Throughout this warring period, the sole objective was the defence of their land and the defeat of their opponents. In doing so, "Bushi" or warriors were trained in how to kill their enemies without the unnecessary prolonging of death. This then formed one of the central tenets of 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 the varied techniques required to meet all happenings in sword fighting. Therefore, free practice or sparring was then encouraged and thereby facilitated the development of the "Shinai" or bamboo sword and protective armour for safety.
Today Kendo followers train themselves primarily by using bamboo swords and learn "Kata" forms by using real metal swords or wooden swords.