The Han unification refers to the process used by the authors of Unicode and the Universal Character Set to map multiple character sets of the CJK languages into a single set of unified glyphs. The Chinese characters are common to Chinese (where they are called "hanzi"), Japanese (where they are called kanji), and Korean (where they are called hanja). Modern Korean, Chinese and Japanese typefaces may represent a given Han character as somewhat different glyphs. However, in the formulation of Unicode, these differences were folded. This unification is referred to as "Han Unification", with the resulting character repertoire sometimes referred to as Unihan.
The process of Han unification was very controversial with most of the opposition coming from the Japanese. Opponents of Han unification state that it steamrollers over thousands of years of cultural tradition, misses many of the subtleties that are one of the most important features of these languages, and renders serious literature and academic research in these languages impossible. Proponents of Han unification state that the Unicode BMP set of unified characters is "good enough" for almost all everyday uses of the languages that use these scripts, that Unicode 3.1 greatly extends this repertoire for academic and literary needs, and that other encodings are also available for specialist academic purposes.
Specialist character sets developed to address, or regarded as not suffering from, these perceived deficiences include: