Kouzo Kaku wrote:
In the first place, a human being possesses a mind and a body, but these alone are not enough. An activating force is required to connect the mind and the body, and this is the ki in Aikido; it is this that completes the trilogy of ki, mind and body.
A possible English translation for ki
is thought, intent or will. If you want to raise your arm, you think it and it is your thought that raises your arm. The mind moves the body. The mind uses ki
to move the body.
K. Kaku goes on to summarize his interview with K. Ueshiba in The Mysterious Power of Ki
Although the founder had a deep interest in philosophy, he probably would not have known of the philosophies of ancient India. However, he appears to have come to the understanding that what he called the 'expert use of ki' is synonymous with that state in which the mind and the body are unified and in harmony with the universe, a state that he achieved through many years of physical and spiritual training. The 'expert use of ki' means making ki work exquisitely and allowing the body to work in harmony with the mind. The founder discovered that the expert use of 'ki' could be realized through subtle changes in breathing.
Because of political differences, some people believe that K. Ueshiba and K. Tohei are ideologically separate. But here you have K. Ueshiba discussing ki as thought, the mind and body as one and being in harmony with the universe. An emphasis on breathing is also stated. This similarity of views could reflect their mutual understanding of the founder.