CJK Unified Ideographs

The Chinese, Japanese and Korean (CJK) scripts share a common background, collectively known as CJK characters. During the process called Han unification, the common (shared) characters were identified and named CJK Unified Ideographs. As of Unicode , Unicode defines a total of 97,680 characters.

The term ''ideographs'' is a misnomer, as the Chinese script is not ideographic but rather logographic.

Until the early 20th century, Vietnam also used Chinese characters (Chữ Nôm), so sometimes the abbreviation CJKV is used.

Sources

The Ideographic Research Group (IRG) is responsible for developing extensions to the encoded repertoires of CJK unified ideographs. IRG processes proposals for new CJK unified ideographs submitted by its member bodies, and after undergoing several rounds of expert review, IRG submits a consolidated set of characters to ISO/IEC JTC 1/SC 2 Working Group 2 (WG2) and the Unicode Technical Committee (UTC) for consideration for inclusion in the ISO/IEC 10646 and Unicode standards. The following IRG member bodies have been involved in the standardization of CJK unified ideographs:

* China
* Hong Kong
* Japan
* South Korea
* North Korea
* Macau
* Taiwan, liaison member represented by the Taipei Computer Association (TCA)
* Vietnam
* Unicode Technical Committee (liaison member, also representing the United States)
* United Kingdom
* SAT (liaison member)

The ideographs submitted by the UTC and the United Kingdom are not specific to any particular region, but are characters which have been suggested for encoding by individual experts. The ideographs submitted by SAT are required for the SAT Daizōkyō text database.

The table below gives the numbers of encoded CJK unified ideographs for each IRG source for Unicode 16.0. The total number of characters (260,840) far exceeds the number of encoded CJK unified ideographs (97,680) as many characters have more than one source.

UTC sources

The majority of characters submitted by the UTC to the IRG are derived from Unicode Technical Committee (UTC) documents. Other sources include:

* '' ABC Chinese-English Dictionary'' by John DeFrancis
* The Adobe-CNS1 glyph collection
* The Adobe-Japan1 glyph collection
* A Complete Checklist of Species and Subspecies of Chinese Birds (中国鸟类系统检索)
* The Great Nom Dictionary (Đại Tự Điển Chữ Nôm)
* Annotations to ''Shuowen Jiezi'' (annotated by Duan Yucai)
* GB18030-2000
* Required Character List Supplied by the Church of Jesus Christ of Latter-day Saints (Hong Kong)
* New Commercial Dictionary (商务新词典), Hong Kong
* Modern Chinese Dictionary (现代汉语词典), by Chinese Academy of Social Sciences, Linguistics Research Institute, Dictionary Editorial Office
* Working Group (WG2) documents

Ordering

The ordering of CJK Unified Ideographs within Unicode blocks (not counting those added to the block later) was initially determined by consulting the following four dictionaries. Primarily, they were arranged in Kangxi Dictionary order, with the other dictionaries consulted, in order, for characters not found in the Kangxi Dictionary, to determine which Kangxi Dictionary character they should follow in the ordering.

# Kangxi Dictionary
# Dai Kan-Wa Jiten
# Hanyu Da Zidian
# Dae Jaweon

This system is not used for more recently-added Unicode blocks. The Ideographic Research Group no longer uses the Dae Jaweon, nor the Dai Kan-Wa Jiten, in its work. The Kangxi Dictionary and Hanyu Da Zidian are still used both in existing character source references, and as potential replacements for existing source references discovered to be erroneous. Similarly, although a (real or virtual) Kangxi Dictionary index was previously provided as part of the submission data for UTC-source characters, this is no longer the case. Instead, the stroke type of the first residual stroke (first stroke which does not form part of the radical) is supplied with all submitted characters, and used to order characters with the same radical and stroke count within the new Unicode block.

CJK Unified Ideographs blocks

CJK Unified Ideographs

The basic block named '' CJK Unified Ideographs'' (4E00–9FFF) contains 20,992 basic Chinese characters in the range U+4E00 through U+9FFF. The block not only includes characters used in the Chinese writing system but also kanji used in the Japanese writing system, hanja in Korea, and chữ Nôm characters in Vietnamese. Many characters in this block are used in all three writing systems, while others are in only one or two of the three.

This block is also known as the ''Unified Repertoire and Ordering'' (URO), especially when it needs to be differentiated from the other CJK Unified Ideographs blocks.

The first 20,902 characters in the block are arranged according to the Kangxi Dictionary ordering of radicals. In this system the characters written with the fewest strokes are listed first. The remaining characters were added later, and so are not in radical order.

The block is the result of Han unification, which was somewhat controversial within East Asia. Since single characters used in more than one of Chinese, Japanese and Korean were coded in the same location, and the modern typographical conventions and handwriting curricula differ slightly between regions (not necessarily along language boundaries—for example, Hong Kong and Taiwan, which both use Traditional Chinese, have slightly different local conventions), the appearance of a selected glyph could depend on the particular font being used. However, the URO applies the ''source separation rule'', meaning that pairs of characters treated as distinct in a character set used as a source for the URO (e.g. JIS X 0208 as used in e.g. Shift JIS) would remain pairs of separate characters in the new Unicode encoding.

Using variation selectors, it is possible to specify certain variant CJK ideograms within Unicode. The Adobe-Japan1 character set, which has 14,684 ideographic variation sequences, is an extreme example of the use of variation selectors.

Charts

4E00-62FF,
6300-77FF,
7800-8CFF,
8D00-9FFF.

Sources

Note: Most characters appear in multiple sources, so the sum of individual character counts (108,480) is far greater than the number of encoded characters (20,992).

In Unicode 4.1, 14 HKSCS-2004 characters and 8 GB 18030 characters were assigned to between U+9FA6 and U+9FBB code points. Since then, other additions were added to this block for various reasons, all summarized in the version history section below.

CJK Unified Ideographs Extension A

The block named ''CJK Unified Ideographs Extension A'' (3400–4DBF) contains 6,592 additional characters in the range U+3400 through U+4DBF.

Charts

3400-4DBF.

Sources

Note: Most characters appear in more than one source, so the sum of individual character counts (23,954) is far greater than the number of encoded characters (6,592).

CJK Unified Ideographs Extension B

The block named '' CJK Unified Ideographs Extension B'' (20000–2A6DF) contains 42,720 characters in the range U+20000 through U+2A6DF. These include most of the characters used in the Kangxi Dictionary that are not in the basic CJK Unified Ideographs block, as well as many Hán-Nôm characters that were formerly used to write Vietnamese.

Charts

20000-215FF,
21600-230FF,
23100-245FF,
24600-260FF,
26100-275FF,
27600-290FF,
29100-2A6DF.

Sources

Note: Many characters appear in more than one source, so the sum of individual character counts (99,784) is far greater than the number of encoded characters (42,720).

CJK Unified Ideographs Extension C

The block named '' CJK Unified Ideographs Extension C'' (2A700–2B73F) contains 4,154 characters in the range U+2A700 through U+2B739. It was initially added in Unicode 5.2 (2009).

Charts

2A700-2B73F.

Sources

Note: Some characters appear in more than one source, so the sum of individual character counts (4,634) is greater than the number of encoded characters (4,154).

CJK Unified Ideographs Extension D

The block named '' CJK Unified Ideographs Extension D'' (2B740–2B81F) contains 222 characters in the range U+2B740 through U+2B81D that were added in Unicode 6.0 (2010).

Charts

2B740–2B81F.

Sources

Note: Some characters appear in more than one source, so the sum of individual character counts (239) is greater than the number of encoded characters (222).

CJK Unified Ideographs Extension E

The block named '' CJK Unified Ideographs Extension E'' (2B820–2CEAF) contains 5,762 characters in the range U+2B820 through U+2CEA1 that were added in Unicode 8.0 (2015).

Charts

2B820–2CEAF.

Sources

Note: Some characters appear in more than one source, so the sum of individual character counts (5,919) is greater than the number of encoded characters (5,762).

CJK Unified Ideographs Extension F

The block named '' CJK Unified Ideographs Extension F'' (2CEB0–2EBEF) contains 7,473 characters in the range U+2CEB0 through 2EBE0 that were added in Unicode 10.0 (2017). It includes more than 1,000 Sawndip characters for Zhuang.

Charts

2CEB0–2EBEF.

Sources

Note: Some characters appear in more than one source, so the sum of individual character counts (7,775) is greater than the number of encoded characters (7,473).

CJK Unified Ideographs Extension G

A block named '' CJK Unified Ideographs Extension G'' was added as part of Unicode 13.0 to the Tertiary Ideographic Plane in the range U+30000 through U+3134F, containing 4,939 characters.

Charts

30000–3134F.

Sources

Note: Some characters appear in more than one source, so the sum of individual character counts (5,081) is greater than the number of encoded characters (4,939).

CJK Unified Ideographs Extension H

A block named '' CJK Unified Ideographs Extension H'' was added as part of Unicode 15.0 to the Tertiary Ideographic Plane in the range U+31350 through U+323AF, containing 4,192 characters.

Charts

31350–323AF.

Sources

Note: Some characters appear in more than one source, so the sum of individual character counts (4,309) is greater than the number of encoded characters (4,192).

CJK Unified Ideographs Extension I

A block named '' CJK Unified Ideographs Extension I'' was added as part of Unicode to the Supplementary Ideographic Plane in the range U+2EBF0 through U+2EE5F, containing 622 characters.

Charts

2EBF0–2EE5F.

Sources

Note: Some characters appear in more than one source, making the sum of individual character counts (625) more than the number of encoded characters (622).

CJK Compatibility Ideographs

The block named '' CJK Compatibility Ideographs'' (F900–FAFF) was created to retain round-trip compatibility with other standards.

However, twelve characters in this block actually have the "Unified Ideograph" property: U+FA0E 﨎, U+FA0F 﨏, U+FA11 﨑, U+FA13 﨓, U+FA14 﨔, U+FA1F 﨟, U+FA21 﨡, U+FA23 﨣, U+FA24 﨤, U+FA27 﨧, U+FA28 﨨, and U+FA29 﨩. None of the other characters in this and other "Compatibility" blocks relate to CJK unification.

While 龜 and 亀 are not considered unifiable, is considered a duplicate to .

Charts

F900–FAFF.

Sources

Note: All characters appear in more than one source, so the sum of individual character counts (40) is greater than the number of encoded characters (12).

Known issues

Disunification

U+4039

The character U+4039 (䀹) was a unification of two different characters (one with jiā 夾 phonetic and one with shǎn 㚒 phonetic) until Unicode 5.0. However, they were lexically different characters that should not have been unified; they have different pronunciations and different meanings.

The proposal of disunification of U+4039 was accepted for Unicode 5.1, encoding a new character at U+9FC3 (鿃) to represent shǎn.

Other 3 glyphs in Extension B

In CJK Unified Ideographs Extension B, some characters are incorrectly unified with others. These characters include U+2017B (𠅻), U+204AF (𠒯) and U+24CB2 (𤲲). The first two characters contained a wrong unification of Chinese Mainland and Vietnamese source of their glyph, while the last one unifies the Chinese Mainland and Taiwanese ones.

Unifiable variants and exact duplicates

Also in CJK Unified Ideographs Extension B, hundreds of glyph variants were encoded by mistake. Additionally, an ISO/IEC JTC 1/SC 2 report has found that six exact duplicates (where the same character has inadvertently been encoded twice) and two semi-duplicates (where the CJK-B character represents a ''de facto'' disunification of two glyph forms unified in the corresponding BMP character) were encoded by mistake:
* U+34A8 㒨 = U+20457 𠑗 : U+20457 is the same as the China-source glyph for U+34A8, but it is significantly different from the Taiwan-source glyph for U+34A8
* U+3DB7 㶷 = U+2420E 𤈎 : same glyph shapes
* U+8641 虁 = U+27144 𧅄 : U+27144 is the same as the Korean-source glyph for U+8641, but it is significantly different from the Chinese Mainland-, Taiwan- and Japan-source glyphs for U+8641
* U+204F2 𠓲 = U+23515 𣔕 : same glyph shapes, but ordered under different radicals
* U+249BC 𤦼 = U+249E9 𤧩 : same glyph shapes
* U+24BD2 𤯒 = U+2A415 𪐕 : same glyph shapes, but ordered under different radicals
* U+26842 𦡂 = U+26866 𦡦 : same glyph shapes
* U+FA23 﨣 = U+27EAF 𧺯 : same glyph shapes (U+FA23 﨣 is a unified CJK ideograph, despite its name "CJK COMPATIBILITY IDEOGRAPH-FA23.")

Other CJK ideographs in Unicode, not Unified

Apart from the ten blocks of "Unified Ideographs," Unicode has about a dozen more blocks with not-unified CJK-characters. These are mainly CJK radicals, strokes, punctuation, marks, symbols and compatibility characters. Although some characters have their (decomposable) counterparts in other blocks, the usages can be different. An example of a not-unified CJK-character is in the CJK Symbols and Punctuation block. Although it is not covered under "CJK Unified Ideographs", it is treated as a CJK-character for all other intents and purposes.

Four blocks of compatibility characters are included for compatibility with legacy text handling systems and older character sets:
* CJK Compatibility (3300–33FF)
* CJK Compatibility Forms (FE30–FE4F)
* CJK Compatibility Ideographs (F900–FAFF)
* CJK Compatibility Ideographs Supplement (2F800–2FA1F)
They include forms of characters for vertical text layout and rich text characters that Unicode recommends handling through other means. Therefore, their use is discouraged.

Font support

The blocks CJK Unified Ideographs and CJK Unified Ideographs Extension A, being parts of the Basic Multilingual Plane, are supported by the majority of the CJK fonts. However, Japanese and Korean fonts usually have fewer characters (about 13,000 and 8,000, respectively) than Chinese. Extensions B, C, D are supported by additional fonts MingLiU-ExtB, MingLiU_HKSCS-ExtB, PMingLiU-ExtB, SimSun-ExtB included in Microsoft Windows since Vista.

Unicode version history

See also

*Han unification
*List of Unicode characters
*List of CJK fonts
* Ideographic Research Group
* Chinese cultural sphere

Notes

References

External links

UK-Source Ideographs
(Documents IRG N2107R2 and IRG N2232R)

{{Unicode navigation

CJK, Unicode CJK Unified Ideographs
Chinese character encodings