Editing CJK characters (section)

== Encoding ==
The number of characters required for complete coverage of all these languages' needs cannot fit in the 256-character code space of 8-bit [[character encoding]]s, requiring at least a 16-bit fixed width encoding or multi-byte variable-length encodings. The 16-bit fixed width encodings, such as those from [[Unicode]] up to and including version 2.0, are now deprecated due to the requirement to encode more characters than a 16-bit encoding can accommodate—Unicode 5.0 has some 70,000 Han characters—and the requirement by the Chinese government that software in China support the [[GB 18030]] character set.

Although CJK encodings have common character sets, the encodings often used to represent them have been developed separately by different East Asian governments and software companies, and are mutually incompatible. [[Unicode]] has attempted, with some controversy, to unify the character sets in a process known as [[Han unification]].

CJK character encodings should consist minimally of Han characters plus language-specific phonetic scripts such as [[pinyin]], [[bopomofo]], hiragana, katakana and hangul.<ref>{{FOLDOC|CJK}}</ref>

CJK character encodings include:
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* [[Big5]] (the most prevalent encoding before Unicode was implemented)
* [[Chinese Character Code for Information Interchange|CCCII]]
* [[CNS 11643]] (official standard of [[Republic of China (Taiwan)|Republic of China]])
* [[EUC-JP]]
* [[EUC-KR]]
* [[GB 2312]] (subset and predecessor of GB 18030)
* [[GB 18030]] (mandated standard in the [[People's Republic of China]])
* Giga Character Set (GCS)
* [[ISO 2022-JP]]
* [[ISO-2022-KR]]
* [[KS X 1001]]
* [[KPS 9566]]
* [[Shift-JIS]]
* [[TRON (encoding)|TRON]]
* [[Unicode]]
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The CJK character sets take up the bulk of the assigned [[Unicode]] code space. There is much controversy among Japanese experts of Chinese characters about the desirability and technical merit of the [[Han unification]] process used to map multiple Chinese and Japanese character sets into a single set of unified characters.{{Citation needed|date=March 2011}}

All three languages can be written both [[Horizontal and vertical writing in East Asian scripts|left-to-right and top-to-bottom]] (right-to-left and top-to-bottom in ancient documents), but are usually considered left-to-right scripts when discussing encoding issues.