C-25: How can I input single-width katakana (JIS X0201 katakana)?

Ken Shibata <shibata@sgi.co.jp> writes:

  To input single-width katakana, Mule provides two emacs lisp files,
  i.e. jisx0201.el and its/han-kata.el.  jisx0201.el defines
  fence-hankaku-katakana (bound to M-x in fence-mode), which converts
  all double-width katakana and hiragana in fence-mode at once.
  its/han-kata.el defines its:select-hankaku-katakana (bound to M-C-x
  in fence-mode; C-x C-k x otherwise), which converts roma-ji into
  single-width katakana.

  Furthermore, jisx0201.el defines hankaku-katakana-region and
  zenkaku-katakana-region (or -paragraph/-sentence/-word).  These
  functions convert strings all at once.  its/han-kata.el loads
  jisx0201.el, so you can load either of them in your .emacs.  But
  note that loading these files takes fairly long time.  If you often
  input single-width katakana, it is recommended to pre-load them in
  site-init.el.

  To summarise,

  1) In fence-mode,
     o type M-x to convert kana to single-width.
     o type M-h to revert single-width katakana to double-width
       hiragana.
     o type M-k to revert single-width katakana to double-width
       katakana.

  2) Out of fence-mode,
     o type C-x C-k x to make typed roma-ji be converted to
       single-width katakana.
     o type C-x C-k h to make typed roma-ji be converted to
       double-width hiragana.

  3) In fence-mode,
     o type M-C-x to make typed roma-ji be converted to single-width
       katakana.
     o type M-C-h to make typed roma-ji be converted to double-width
       hiragana.

  (If you have exchanged BS and DEL by bobcat.el or something like
  that, and are using ESC key to input Meta, then M-C-h means ESC
  DEL.)