I know someone who works at a Japanese preschool in America. Several months ago she told me that her coworkers were considering investing in a holdings company which described itself as tied to the value of XRP. They claimed that XRP was poised to go up due to some announcements that are coming down the pipeline regarding XRP and banks in Japan.
At least a few of her coworkers did ultimately invest. I don’t know how much, and I don’t remember exactly when. It was definitely over 6 months ago and well before the recent jump. They are not techies or in anyway following this sort of technology, so I was very surprised to be hearing about it from them rather than the other way around, and that it has reached the Japanese community here in America. Given the generally homogenous nature of Japanese culture, as you pointed out, the fact that at least a few did buy in shows that there is some perceived creditability amongst the group.
So there you have it — some anecdotal evidence in support of your claim.