Bob: "Many useful aspects of the culture carry great weight in Japanese society even today."
Like elder abuse?
Your suggestion that Kiryu is 5'9", rather than the 5'6" reported elsewhere, is significant. Is that verified? It would make a big difference, and would make this performance a whole lot more credible.
I would still need further verification--which, if forthcoming, would be absolutely excellent. Also, if he is 5'9" and especially if he grows another inch or two, we can look forward to consistent sub-10 clockings from him.