"Ota, Takaaki" <Takaaki.Ota@am.sony.com> writes:

> Now I fully understand the situation.  Thanks for the detail
> explanation.  I am sorry for the shoddy platform I have to use.

Does the following patch help?  It basically changes the characters that
Emacs looks for in a font to classify it as capable of displaying kana;
from hiragana "ka" only; to hiragana, katakana and half-width katakana
"ka", and the prolonged sound mark that is missing from the first font
your system currently finds for displaying Japanese.