{{Short description|Logographs in shared East Asian written tradition}} {{About||help with CJK character display|Help:Multilingual support (East Asian)|selfref=true}} [[File:That old man is 72 years old.svg|thumb|342x342px|Translation of "That old man is 72 years old" in [[Vietnamese language|Vietnamese]], [[Cantonese]], [[Mandarin Chinese|Mandarin]] (in [[Simplified Chinese characters|simplified]] and [[Traditional Chinese characters|traditional characters]]), [[Japanese language|Japanese]], and [[Korean language|Korean]]]] In [[internationalization and localization|internationalization]], '''<abbr title="Chinese, Japanese and Korean">CJK</abbr> characters''' is a collective term for [[graphemes]] used in the [[Written Chinese|Chinese]], [[Japanese writing system|Japanese]], and [[Korean writing system]]s, which each include [[Chinese characters]]. It can also go by '''CJKV''' to include [[Chữ Nôm]], the Chinese-origin [[logogram|logographic]] script formerly used for the [[Vietnamese language]], or '''CJKVZ''' to also include [[Sawndip]], used to write the [[Zhuang languages]].
== Character repertoire == [[Standard Mandarin Chinese]] and [[Standard Cantonese]] are written almost exclusively in [[Chinese characters]]. Over 3,000 characters are required for general literacy, with up to 40,000 characters for reasonably complete coverage. Japanese uses fewer characters—general literacy in Japanese can be expected with 2,136 characters. The use of Chinese characters in Korea is increasingly rare, although idiosyncratic use of Chinese characters in proper names requires knowledge (and therefore availability) of many more characters. {{As of|2013}}, some South Korean students were still expected to learn [[Basic Hanja for educational use|1,800 characters]].<ref>{{Cite book |last=Lunde |first=Ken |title=CJKV information processing |date=2009 |publisher=O'Reilly |isbn=978-0-596-51447-1 |edition=2nd |location=Beijing, Boston, Farnham, Sebastopol, Tokyo}}</ref>
Other scripts used for these languages, such as [[bopomofo]] and the [[Latin script|Latin]]-based [[pinyin]] for Chinese, [[hiragana]] and [[katakana]] for Japanese, and [[hangul]] for Korean, are not strictly "CJK characters", although CJK character sets almost invariably include them as necessary for full coverage of the target languages.
The [[Sinology|sinologist]] Carl Leban (1971) produced an early survey of CJK encoding systems.
Until the early 20th century, [[Classical Chinese]] was the written language of government and scholarship in Vietnam. Popular literature in [[Vietnamese language|Vietnamese]] was written in the {{lang|vi|[[chữ Nôm]]}} script, consisting of Chinese characters with many characters created locally. Since the 1920s, the script since then used for recording literature has been the Latin-based [[Vietnamese alphabet]].{{sfnp|Coulmas|1991|pp=113–115}}{{sfnp|DeFrancis|1977}}
===Quadruplication === '''Quadruplication''' ({{lang-zh|四叠字}}, literally "four-fold characters") is a method of forming CJK characters via ideographic repetition. [[Ken Lunde]] describes these characters as "clusters of four or more identical elements, along with three identical elements in a row arranged horizontally or vertically".<ref>{{cite web |last1=Lunde |first1=Ken |title=UTN #43: Unihan Database Property “kStrange” |url=https://www.unicode.org/notes/tn43/ |website=www.unicode.org}}</ref> These characters were mostly used in [[Old Chinese]] writings and are no longer commonly used, except as components in some modern [[Han ideographs]] such as 惙.<ref>{{cite journal |last1=Yuan |first1=Alex |title=A Discussion on the Approach of “Connections” to Chinese Character Studies in Teaching Chinese as a Foreign Language |journal=Chinese Language Teaching Methodology and Technology |date=11 August 2020 |volume=3 |issue=1 |pages=46 |url=https://engagedscholarship.csuohio.edu/cltmt/vol3/iss1/6 |access-date=24 December 2025 |issn=2572-1739}}</ref>
====Examples==== {| class="wikitable sortable" |- ! Quadruplicate Character !! English Meaning !! Notes |- | 𪚥 || (obsolete) verbose; talkative || 龍 ("[[dragon]]" in a grid of four) |- | 䲜 || the appearance of many kinds of fish || used in the [[chengyu]] 生活䲜䲜 |- | 㸚 || (obsolete) sparse and clear || only found in historical dictionaries such as the [[Shuowen Jiezi]] |}
== 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: {{div col|colwidth=40em}} * [[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]] {{div col end}}
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.
== Legal status == Libraries cooperated on encoding standards for [[JACKPHY]] characters in the early 1980s. According to [[Ken Lunde]], the abbreviation "CJK" was a registered [[trademark]] of [[Research Libraries Group]]<ref name=":0">[http://www.csse.monash.edu.au/~jwb/cjk.inf Ken Lunde, 1996]</ref> (which merged with [[OCLC]] in 2006). The trademark owned by OCLC between 1987 and 2009 has now expired.<ref>[http://trademarks.justia.com/736/38/cjk-73638777.html Justia listing]</ref>
== See also == * [[Chinese character description languages]] * [[Chinese character encoding]] * [[Chinese input methods for computers]] * [[CJK Compatibility Ideographs]] * [[Chinese character strokes]] * [[CJK Unified Ideographs]] * [[Complex Text Layout languages]] (CTL) * [[Input method editor]] * [[Japanese language and computers]] * [[Korean language and computers]] * [[List of CJK fonts]] * [[Sinoxenic]] * [[Variable-width encoding]] * [[Vietnamese language and computers]]
== References == {{Reflist}}
===Works cited=== * {{cite book |last=Coulmas |first=Florian |title=The writing systems of the world |url=https://archive.org/details/writingsystemsof0000coul |publisher=Blackwell |year=1991 |isbn=978-0-631-18028-9 |url-access=registration}} * {{cite book |last1=DeFrancis |first1=John |title=Colonialism and language policy in Viet Nam |date=1977 |publisher=Mouton |location=The Hague |isbn=978-90-279-7643-7}}
==Sources== {{refbegin}} * [[John DeFrancis|DeFrancis, John]]. ''[[The Chinese Language: Fact and Fantasy]]''. Honolulu: University of Hawaii Press, 1990. {{ISBN|0-8248-1068-6}}. * Hannas, William C. ''Asia's Orthographic Dilemma''. Honolulu: University of Hawaii Press, 1997. {{ISBN|0-8248-1892-X}} (paperback); {{ISBN|0-8248-1842-3}} (hardcover). * Lemberg, Werner: The CJK package for LATEX2ε—Multilingual support beyond babel. TUGboat, Volume 18 (1997), No. 3—Proceedings of the 1997 Annual Meeting. * Leban, Carl. ''[https://books.google.com/books?id=ePLMGwAACAAJ Automated Orthographic Systems for East Asian Languages (Chinese, Japanese, Korean)]'', State-of-the-art Report, Prepared for the Board of Directors, Association for Asian Studies. 1971. * [[Ken Lunde|Lunde, Ken]]. ''CJKV Information Processing''. Sebastopol, Calif.: O'Reilly & Associates, 1998. {{ISBN|1-56592-224-7}}. {{refend}}
== External links == * [http://www.linfo.org/cjkv.html CJKV: A Brief Introduction] * [http://tug.org/TUGboat/Articles/tb18-3/cjkintro600.pdf Lemberg CJK article from above, TUGboat18-3] * [http://www.wenlin.com/cdl/#jarg On "CJK Unified Ideograph"], from Wenlin.com * [https://web.archive.org/web/20130624130411/http://homepage.ntlworld.com/jonathan.deboynepollard/FGA/unicode-cjkv-character-set-rationalization.html FGA: Unicode CJKV character set rationalization]
{{CJK ideographs in Unicode}}
[[Category:Encodings of Asian languages]] [[Category:Languages of East Asia]] [[Category:Natural language and computing]] [[Category:Chinese-language computing]] [[Category:Japanese-language computing]] [[Category:Korean-language computing]] [[Category:Writing systems using Chinese characters]]