It seems like I read an article on this, I was pretty sure it was at toyama-ryu.org in the history of the art, starting with gunto soho, and later evolutions - which I can't recall. That site appears to be expired, so I can't find the article, but I am guessing you have seen this article as well, and may well have resourc rines that the article used for that reference.
Does that ring any bells?
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I found an article at: http://dev.nsgroupllc.com/smaa-hq.co...p?articleid=14 which might or might not be the same article. I can't say whether the article is authoritative, I'll leave judgement to those of you better qualified than I.