Why is Unicode missing some characters from the Big Five character set?
The “Big Five” character set is an industrial standard commonly used for traditional Chinese. There are, however, several versions of the Big Five in common use, generally representing extensions of the formal standard. There are two main versions, “plain Big Five” and “ETEN Big Five” as well as numerous vendor- or platform- specific extensions. In recent years, there have been further extensions such as the Hong Kong Extension to Big Five and Big Five Plus. The initial, un-extended Big Five was the standard version of the character set at the time that the Unicode Standard, Version 1.0, was under development, and Unicode was designed to cover its ideographic repertoire completely. This is reflected in the data files supplied by the Unicode Consortium. Some vendors provide vendor-specific tables showing mapping data for their custom Big Five extensions and Unicode. The Unicode Consortium does not, however, provide data on every known dialect of the Big Five, so it is possible that a pa
