Morihei Ueshiba, now called O-Sensei ("Great Teacher"), the founder of Aikido. Born in 1883 in Wakayama Prefecture, Japan. He sought out and studied under masters in many traditional martial arts, eventually becoming expert at a number of styles of jujitsu (unarmed combat), kenjitsu (swordfighting), and sojitsu (spear fighting). Dissatisfied with mere strength and technical mastery, he also immersed himself in religious and philosophical studies. The stories of his immense physical strength and martial prowess are impressive enough, but more important is the legacy of nonviolence and human integrity he left to mankind.

In early 20th-century Japan, involvement in the martial arts was a competitive and dangerous business. Contests, feuds and rivalries often resulted in injuries and even deaths. The formulation of Aikido dates from an incident that occurred in 1925. In the course of a discussion about martial arts, a disagreement arose between O-Sensei and a naval officer who was a fencing instructor. The officer challenged O-Sensei to a match, and attacked with a wooden sword. O-Sensei faced the officer unarmed, and won the match by evading blows until his attacker dropped from exhaustion. He later recalled that he could see his opponent's moves before they were executed, and that this was the beginning of his enlightenment. He had defeated an armed attacker without hurting him - without even touching him.

O-Sensei later wrote: "Budo (the Martial Way) is not felling the opponent by our force; nor is it a tool to lead the world into destruction with arms. True Budo is to accept the spirit of the universe, keep the peace of the world, correctly produce, protect, and cultivate all things in nature."