Koichi Tohei (January 20, 1920 – May 19, 2011) was aikido's first 10th dan and served as Chief Instructor of Hombu Dojo (the Aikido World Headquarters) for many years.
He later founded the Ki Society and its style of aikido, officially Shin Shin Toitsu Aikido (literally "aikido with mind and body unified"), commonly known as Ki-Aikido.
Tohei first met O-sensei at age 20 in 1940 already possessing extensive judo experience. He became Ueshiba's student immediately. Koïchi Tohei was a leader in introducing aikido to the West, mainly through regular teaching journeys to Hawaii, the continental US, and Europe.
After serving as Chief Instructor at Aikikai Hombu Dojo for many years, conflicts motivated him to break away from the Aikikai. On 1 May 1974, Koichi Tohei officially left the Aikikai organization to concentrate on his newly created Ki-aikido and Ki-society. This breakup came as a shock to many aikidoka throughout the world. This, in turn, led to several dojos breaking with the Aikikai and joining Tohei in his new style.
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