Variations of mapping from Japanese encodings to Unicode

Unfortunately, different systems use different mapping tables from
Shift-JIS to Unicode.  The same thing applies to ISO-2022-JP and
Japanese EUC.  Such mapping tables are very unlikely to disappear
soon.  More about this, see XML Japanese Profile at:
       
       http://www.w3.org/TR/japanese-xml

Such unstable mapping spoils interoperatibility and is fatal
especially for digital signature.  Although we do not have any really
good solutions, we can assign different charset names to different
mapping tables.

For this reason, I am going to propose quite a few charsets for
Shift-JIS, Japanese EUC, and ISO-2022-JP.  They are new charsets
rather than aliases of existing charsets (i.e., shift_jis, euc-jp,
iso-2022-jp), which does not have agreed mapping tables.  

Cheers,

MURATA Makoto