CJK Unified Ideographs

CJKV ideograph 次 in traditional and simplified Chinese, Korean, Vietnamese and Japanese.

The Chinese, Japanese and Korean (CJK) scripts share a common background. In the process called Han unification the common (shared) characters were identified, and named "CJK Unified Ideographs". Unicode defines a total of 74,617 CJK Unified Ideographs.[1]

The terms ideographs or ideograms may be misleading, since the Chinese script is not strictly a picture writing system.

Historically, Vietnam used Chinese ideographs too, so sometimes the abbreviation "CJKV" is used. This system was replaced by the Latin-based Vietnamese alphabet in the 1920s.

CJK Unified Ideographs blocks

CJK Unified Ideographs

The basic block named CJK Unified Ideographs (4E00–9FFF) contains 20,941 basic Chinese characters in the range U+4E00 through U+9FCC. The block not only includes characters used in the Chinese writing system but also kanji used in the Japanese writing system and hanja, whose use is diminishing in Korea. Many characters in this block are used in all three writing systems, while others are in only one or two of the three. Chinese characters were also used in Vietnam's Nôm script (now obsolete). 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 sequence.

The block is the result of Han unification,[2] which was somewhat controversial in the Far East.[3] Since Chinese, Japanese and Korean characters were coded in the same location, the appearance of a selected glyph could depend on the particular font being used. However, the source separation rule states that characters encoded separately in an earlier character set would remain separate in the new Unicode encoding.[4]

Using variation selectors, it is possible to specify certain variant CJK ideograms within Unicode. The Adobe-Japan1 character set proposal, which actually calls for 14,658 ideographic variation sequences, is an extreme example of the use of variation selectors.[5]

Charts

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

Sources

The code points in this block are assigned under Source Separation Rule.

China
Code Standard Character count note
G0 GB 2312-80 6763
G1 GB 12345-90 2352
G3GB 7589-87 unsimplified form7237
G5GB 7590-87 unsimplified form7039
G7Modern Chinese general character chart42
G8GB 8565-89290
Taiwan
Code Standard Character count note
T1 CNS 11643-1986 plane 1 5401+9
T2 CNS 11643-1986 plane 2 7650
TE CNS 11643-1986 plane 14 6319+239+10 239 from CCIII, 10 from XCCS
Japan
Code Standard Character count note
J0 JIS X 0208-90 6335+1
J1 JIS X 0212-90 5801
South Korea
Code Standard Character count note
K0 KS C 5601-87 (now KS X 1001:2004) 4888 includes 268 duplicates
K1 KS C 5657-91 (now KS X 1002:2004) 2856
K2 PKS C 5700-1:1994 (now KS X 1027-1:2011) 7911
K4 PKS 5700-3:1998 (now KS X 1027-3:2011) 4
Others

In Unicode 4.1, 14 HKSCS-2004 characters and 8 GB 18030 characters were assigned to between U+9FA6 and U+9FBB code points.

CJK Unified Ideographs Extension A

The block named CJK Unified Ideographs Extension A (3400–4DBF) contains 6,582 additional characters in the range U+3400 through U+4DB5 that were added in Unicode 3.0 (1999).

Charts

3400-4DBF.

Sources

China
Code Standard
GE GB 16500-95
GS Singapore CJK ideographs
Taiwan
Code Standard note
T3 CNS 11643-1992 plane 3
T4 CNS 11643-1992 plane 4
T5 CNS 11643-1992 plane 5
T6 CNS 11643-1992 plane 6
T7 CNS 11643-1992 plane 7
TF CNS 11643-1992 plane 15
Japan
Code Standard note
JA Unified Japanese IT Vendors Contemporary Ideographs, 1993
South Korea
Code Standard note
K3 PKS C 5700-2:1994 (now KS X 1027-2:2011)
K4 PKS 5700-3:1998 (now KS X 1027-3:2011)
Vietnam
Code Standard note
V0 TCVN 5773:1993
V1 TCVN 6056:1995

CJK Unified Ideographs Extension B

The block named CJK Unified Ideographs Extension B (20000–2A6DF) contains 42,711 characters in the range U+20000 through U+2A6D6 that were added in Unicode 3.1 (2001). 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 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

CJK Unified Ideographs Extension C

The block named CJK Unified Ideographs Extension C (2A700–2B73F) contains 4,149 characters in the range U+2A700 through U+2B734 that were added in Unicode 5.2 (2009).

Charts

2A700-2B73F.

Sources

China
Japan
South Korea
North Korea
Vietnam
Other

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.

CJK Unified Ideographs Extension E (projected)

The CJK Unified Ideographs Extension E block was earlier provisionally named Extension D.

CJK-E was originally intended to include another 16,000+ characters not present in CJK-C. However, in May 2007 the Republic of China (Taiwan) withdrew 6,545 personal name usage characters deemed no longer in use,[6] in May 2013 China withdrew 6 characters,[7] and many others were later withdrawn or moved to CJK-F (projected),[8] so the current version includes 5,762 new characters. CJK-E including 5,762 Han characters will be new in Unicode 8.0.[9]

CJK Unified Ideographs Extension F (projected)

The IRG agreed on the proposal for a CJK Unified Ideographs Extension F at the 38th IRG meeting in June 2012,[10] and work on CJK-F is currently in process.

CJK Compatibility Ideographs

There are four Unicode blocks whose names include the phrase "CJK Compatibility":

The CJK Compatibility Ideographs block contains twelve characters for CJK Unified Ideographs compatibility. None of the other characters in these blocks relate to CJK Unification. See Unified ideographs outside of the blocks below.

Known issues

Disunification of 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[11] was accepted and the new character is encoded at U+9FC3 in Unicode 5.1.

Unified ideographs outside of the blocks

The CJK Compatibility Ideographs block (F900-FAFF) is not part of the "unified ideographs" list, but includes twelve characters that are in fact classified and named as unified ideographs: FA0E, FA0F, FA11, FA13, FA14, FA1F, FA21, FA23, FA24, FA27, FA28 and FA29.

Unifiable variants and exact duplicates in Extension B

In CJK Unified Ideographs Extension B, hundreds of glyph variants were encoded.[12] In addition to the deliberate encoding of close glyph variants, 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:[13]

Other CJK Ideographs in Unicode, not Unified

Apart from the five 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.

Four blocks (one of which is labelled "Unified Ideographs") of compatibility characters are included for compatibility with legacy text handling system and other legacy character sets. 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.

Usually, compatibility characters are those that would not have been encoded except for compatibility and round-trip convertibility with other standards. However, the amount of CJK ideographs within any non-Unicode standard is too big to fit into Unicode's CJK Compatibility Ideographs blocks. Instead, code points are assigned when the affected characters are approved by the Unicode Consortium, but have yet to assign any code points within the CJK Unified Ideographs blocks.

Unicode version history

CJK unified Ideographs additions per Unicode version
Unicode version Addition Plane Characters added Total Characters
1.0 (1991) CJK Unified Ideographs Basic Multilingual Plane (BMP) 20,902 20,914
CJK Compatibility Ideographs BMP 12
3.0 (1999) CJK Unified Ideographs Extension A BMP 6,582 27,496
3.1 (2001) CJK Unified Ideographs Extension B Supplementary Ideographic Plane (SIP) 42,711 70,207
4.1 (2005) CJK Unified Ideographs: Ideographs from HKSCS-2004 and GB 18030-2000 not in ISO 10646 BMP 22 70,229
5.1 (2008) CJK Unified Ideographs: Ideographs from Adobe Japan and disunification of U+4039 BMP 8 70,237
5.2 (2009) CJK Unified Ideographs Extension C SIP 4,149 74,394
8 other characters from ARIB #47, #95, #93 and HKSCS BMP 8
6.0 (2010) CJK Unified Ideographs Extension D SIP 222 74,616
6.1 (2012) 1 character corresponding to Adobe-Japan1-6 CID+20156 BMP 1 74,617

Notes

  1. ↑ Unicode 6.1 Character Database – property list file
  2. ↑ The Unicode standard 4.0, Appendix A - Han Unification History
  3. ↑ Suzanne Topping, "The secret life of Unicode"
  4. ↑ "Chapter 11 - East Asian scripts", The Unicode standard, 4.0.
  5. ↑ PRI 108: Combined registration of the Adobe Japan1 collection and of sequences in that collection
  6. ↑ IRG N 1306: Request to Withdraw 6545 T-Source from CJK D candidate
  7. ↑ ISO/IEC JTC1/SC2/WG2 N4439
  8. ↑ http://appsrv.cse.cuhk.edu.hk/~irg/irg/irg38/IRGN1872_US_ExtF.pdf
  9. ↑ http://www.unicode.org/charts/PDF/Unicode-8.0/
  10. ↑ http://appsrv.cse.cuhk.edu.hk/~irg/irg/irg38/IRGN1870Resolutions.doc
  11. ↑ Andrew West and John Jenkins, proposal of disunification of U+4039
  12. ↑ unifiable glyph variants
  13. ↑ Cook, Richard (6 October 2003). "Defect Report on Duplicate Encoded CJK Forms" (PDF). ISO/IEC JTC1/SC2/WG2. Retrieved 2012-03-28.

See also

External links