Morihei Ueshiba, referred to as O-Sensei (great teacher) or the founder by Aikido practitioners, was born on December 14, 1883 in Tanabe in present-day Wakayama prefecture. At the age of seventeen he had his first formal training in Tenjin Shinyo-ryu jujutsu. He joined the army in 1903. His affinity for the martial arts was particularly evident in his training; he excelled in bayonet practice. In the period during his military service, 1903-1906, O-Sensei trained in a Yagyu Ryu school in Osaka, possibly Yagyu Shingan Ryu. In the period after 1906, he trained Judo for a short time.

In 1915, O-Sensei met Sokaku Takeda, of Daito-ryu jujutsu for the first time. He soon became one of Takeda’s best students. The techniques of Takeda’s Daito-ryu became the foundation of O-Sensei’s creation, what we now know as Aikido. The name most often used for this martial art during the pre-war years was Aiki Budo.