Han unification is an effort by the authors of Unicode and the Universal Character Set to map multiple character sets of the Han characters of the so-called CJK languages into a single set of unified characters. Han characters are a feature shared in common by written Chinese (hanzi), Japanese (kanji), Korean (hanja) and Vietnamese (chữ Hán).
Modern Chinese, Japanese and Korean typefaces typically use regional or historical variants of a given Han character. In the formulation of Unicode, an attempt was made to unify these variants by considering them as allographs – different glyphs representing the same "grapheme" or orthographic unit – hence, "Han unification", with the resulting character repertoire sometimes contracted to Unihan.
Nevertheless, many characters have regional variants assigned to different code points, such as Traditional 個 (U+500B) versus Simplified 个 (U+4E2A).
Rationale and controversy
The Unicode Standard details the principles...