Video of master Hiroshi Isoyama on Youtube

Rough and hard.
Demonstrates the martial potential of Aikido.
He was a long time student of O-sensei in Iwama.
He is currently chief instructor at the dojo that O-sensei built in Iwama, presently known as Ibaraki-Shibu Dojo.

From Aikido Journal’s Encyclopedia of Aikido:
“ISOYAMA, HIROSHI (b. 14 January 1937). 8th dan Aikikai. B. Ibaragi Prefecture. Civil servant, Aikikai Shihan. Began training in June 1949 becoming an UCHIDESHI in IWAMA Dojo while middle school student. Known for his powerful technique.”

There is also a very interesting interview of Isoyama Shihan on Aikido Journal.
(Link to interview here…)

Excerpt from the interview:

“Since many of your students among the American military police must have been much physically larger than you, did you have to come up with new ways to make your techniques work on them?

I certainly did. Practicing with people like that is completely different from working with people who are smaller than you.
Doing even something like ikkyo against a much larger opponent is very difficult, especially in terms of the way you have to enter and the timing you have to use.
Training with people like that was a great experience from which I learned a lot.
My kata guruma and ganseki otoshi techniques, for example, started out with me trying to teach koshi nage.
When I tried to do koshi nage on some of the taller men I found that they could just step over me; no matter how I tried the technique, I couldn’t manage to throw them because the height difference meant I couldn’t get my hips into a good position in front of theirs.
Then I had the idea to try putting them across my shoulders instead of across my hips, and that’s how I started using those techniques. I wasn’t trying to be rough or flashy, I was just trying to get the techniques to work. Necessity is the mother of invention!”