Re: causing no (serious) harm
From the book reviews on this site,
concerning Aikido & the Dynamic Sphere:
The authors of this book studied aikido in the U.S. and Europe. Although they were only shodan when they wrote the book, the authors consulted with many of the top teachers in the states at that time, including Yoshimitsu Yamada sensei, head of New York Aikikai. (Mike Lee)
Anyone else knows more?
ps to David Valdez: thanks for keeping the thread on track.