CJK Unified Ideographs

During the process called Han unification, the common (shared) characters were identified and named CJK Unified Ideographs.

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

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 table below gives the numbers of encoded CJK unified ideographs for each IRG source for Unicode 16.0.

The Ideographic Research Group no longer uses the Dae Jaweon,[7] nor the Dai Kan-Wa Jiten,[8] in its work.

[10] 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.

[15] 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),[16] the appearance of a selected glyph could depend on the particular font being used.

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

[21] 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).

[21] 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).

[21] 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).

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.

The proposal of disunification of U+4039[27] was accepted for Unicode 5.1, encoding a new character at U+9FC3 (鿃) to represent shǎn.

[28] Also in CJK Unified Ideographs Extension B, hundreds of glyph variants were encoded by mistake.

An example of a not-unified CJK-character is U+3007 〇 IDEOGRAPHIC NUMBER ZERO in the CJK Symbols and Punctuation block.

Extensions B, C, D are supported by additional fonts MingLiU-ExtB, MingLiU_HKSCS-ExtB, PMingLiU-ExtB, SimSun-ExtB included in Microsoft Windows since Vista.