Yes, indeed. I’ve had a professional interest in Japanese typography for many years, having worked on many Japanese dictionaries and other publications, but this document contains much that I didn’t know.

+1 to that – in the document's note sections there are a lot of typographical rules of style/aesthetic rules of thumb that are probably out of the scope of a W3C-style purely algorithmic specification, are very useful (e.g. indentations, conventional head/subhead/running section formatting, etc.)