This is from pages 64-65 http://etheses.dur.ac.uk/4081/1/4081_1600.pdf?UkUDh:CyT
"During World War I I, the tension between Ueshiba's spiritual beliefs and what he saw as the destructive aims of the military came to a climax, provoking a crisis which led to his withdrawal to the countryside to resolve the paradox. He became increasingly critical of the politicians and military, whom he described as having conspired to "misrepresent" true budd which should be "the
embodiment of peace, love and etiquette".
That the events of the war impacted greatly on his thinking is apparent from his preoccupation, in talks given in the 1950s, with the need to create a peaceful world community in which there would be no need for "hydrogen bombs". The problem, as he saw it, related to the nature and function of physical force:
When speaking of physical force, no matter how strong a person can be said to be, there is a limit to his strength. When physical power is used it is always defeated. The Japanese participation in the last World War [II] was an example of this. It is mistaken to resort to the use of maximum force in the Japanese martial arts (budo). On the other hand, it appears at first glance that by rejecting the use of force in the practice of martial arts you reject their essential nature. Can there be such a thing as a martial art which rejects the use of force?...While witnessing the course of the Pacific War, I became deeply distressed and withdrew to the Aikido shrine at Iwama. There I spent three years in deep meditation and ended up reevaluating my training in light of this idea. Finally, I understood the concept underlying martial arts that is, to stop (control) the opponent's weapon.
Martial arts' practice was banned by the occupation forces but Iwama was far enough from the capital for training there not to be noticed. Such was Ueshiba's dissociation from the military at this time, however, that the occupation forces do not appear to have seen him as any kind of threat. As
advisor to the Dai Nihon Butokukai he could have been indicted for war crimes as many of his contemporaries were, but Shioda Gozo notes that this did not happen. On the contrary, Ueshiba was invited to demonstrate aikido to occupation troops at the US military base in Yokohama immediately after the war."