by reading the suggestions from this list, I prepared
an example the Org headers one could use to write
Japanese in Org, with or without furigana signs.

  It's available at this address, under the "furigana-example"
section:

https://github.com/thesoftwarebin/the-emacs-software-bin

  It's there mainly as a reminder to myself, and it's obviously
not perfect, but I just wanted to share. In my environment
(Win 7 + Emacs 24.3 + a recent Org + a newbie user at the
console) the Org file produces proper export to HTML and PDF
output, hope it may work for other users interested in Japanese
writing too.