Koichi Tohei was born in Tokyo in 1920. When he was very young, his family moved to Tochigi prefecture where he spent his childhood. Tohei's health was fragile throughout hischildhood and he frequently was in hospitals and under the care of doctors.
At his father's insistence he took up judo. Having strengthened his body to some degree, at fifteen he earned his black belt and at sixteen entered Keio University's preparatory program. He continued to practice judo enthusiastically, but contracted pleurisy as a result of excessive training and was forced to withdraw from school for a year. Doctors told him he could never do vigorous training again without risking death. Tohei began reading extensively about religion and eastern philosophy and decided to begin practicing the things he was reading about, regardless of the risk. He began training in Zen meditation and then in Misogi, an arduous breathing exercise done in two-day sessions. When he returned to his doctors, all traces of pleurisy had disappeared.
Tohei Sensei demonstrating Jo Kata in 1950's
In 1939, at the age of 19, Tohei met Morihei Ueshiba and became his student. In the short span of half a year he became the founder's representative (dairi) and, having yet to receive any official ranking in aikido, was sent to instruct at the Nakano Police Academy and the private school of Shumei Okawa. In September 1942, Tohei Sensei graduated from Keio University and entered the Toyohashi Officers Preparatory Academy. In February 1942, at 23, he was dispatched to a platoon near the Central China front. He realized through personal experience in battle that he must master calmness and relaxation. Tohei Sensei learned under fire the secret of directing ki and maintaining the one point in the lower abdomen. He gained important insight into his previous training and how it must be applied to daily life.
In August 1946 Tohei Sensei's platoon was demobilized from central China. He once more studied misogi and aikido while at Gokokuji in Otowa, Tokyo. He also studied Tempudo with Tempu Nakamura Sensei. Tempu Nakamura is credited as being the first to teach yoga in Japan. His teachings had a profound influence on Tohei Sensei. Nakamura talked about the importance of positive thinking and taught what he called mind and body unification (shin-shin toitsu do). Tohei Sensei saw that these ideas were fundamental to Aikido and incorporated them as he developed his own systematic way of teaching.