Ted Ehara wrote:
As far as I have been able to determine, the only aikido style that has breathing exercises is the Ki Society.
Koichi Tohei utilized the theories of Tempu Nakamura and applied them to Ki-Aikido. H.E. Davey, a member of Tempukai, the organization that Nakamura Sensei started, writes about Kumbhaka Breathing in his book Japanese Yoga.
Others who have written about breathing are Saotome Sensei in his book Aikido and the Harmony of Nature and Stevens Sensei in his book about Shirata Sensei Aikido : The Way of Harmony. Shirata Sensei gives breathing exercises in the section on Kokyu-ho: Breath-Meditation.
Well, I practice what you would call Iwama style Aikido and we quite frequently do breathing excercises. He also has what he calls a "yoga" class, but I asked him about it one day and he says he just calls it that but is mainly ShinShin-Toitsu (SP?), which I think is a Japanese yoga.