The development of the sword is paralleled by the development of the methods used to wield it. During times of peace, the warriors trained with the sword, and invented new ways to implement it. During war, these theories were tested. After the war ended, those who survived examined what worked and what didn't, and passed their knowledge on. In 1600 A.D., Tokugawa Ieyasu (1543-1616) gained total control of all of Japan, and the country entered a period of prolonged peace that would last until the First World War. During this period, the techniques to use the sword underwent a transition from a primarily utilitarian art for killing, to one encompassing a philosophy of personal development and spiritual perfection.
