interesting. i did a search here and didnt see any mentioning

of his name.

some of my friends in the early 90's talked a lot about him, he was avant garde, plus some more, then.
i'm a fan of his teacher, yahara sensei who's very externally expressive.

anyway good to know yamamoto is still popular.
you prob know, since you're familiar w his work, his daughter, 三本丽美is very established now.