CJK Unified Ideographs Extension B is a Unicode block containing rare and historic CJK ideographs for Chinese, Japanese, Korean, and Vietnamese submitted to the Ideographic Research Group between 1998 and 2000, plus seven gongche characters for kunqu added in Unicode 13.0, and two characters for the Macao Supplementary Character Set added in Unicode 14.0.[3]
The block has dozens of variation sequences defined for standardized variants.[4]
It also has thousands of ideographic variation sequences registered in the Unicode Ideographic Variation Database (IVD).[5][6] These sequences specify the desired glyph variant for a given Unicode character.
It was the only CJK Unified Ideographs Extension block with a UCS2003 source identifier. Since Extension B contained too many characters, the original code charts were produced with a single glyph for all regions. The glyphs were designed by Beijing Zhongyi Electronic Ltd. After the introduction of multi-column code charts on Unicode 5.2, the original glyphs were retained under the UCS2003 source identifier; they were then removed in Unicode 14.0, being redundant as well as misleading.[7] The glyphs are packaged in the "SimSun-ExtB" font distributed with the Simplified Chinese versions of Windows, and do not adhere to the glyphs for the Mainland China region.
Also in CJK Unified Ideographs Extension B, hundreds of glyph variants were encoded.[8] 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:[9]
The following Unicode-related documents record the purpose and process of defining specific characters in the CJK Unified Ideographs Extension B block:
CJK Unified Ideographs CJK Unified Ideographs Extension A CJK Unified Ideographs Extension B CJK Unified Ideographs Extension C CJK Unified Ideographs Extension D CJK Unified Ideographs Extension E CJK Unified Ideographs Extension F CJK Unified Ideographs Extension G CJK Unified Ideographs Extension H CJK Unified Ideographs Extension I CJK Radicals Supplement Kangxi Radicals Ideographic Description Characters CJK Symbols and Punctuation CJK Strokes Enclosed CJK Letters and Months CJK Compatibility CJK Compatibility Ideographs CJK Compatibility Forms Enclosed Ideographic Supplement CJK Compatibility Ideographs Supplement
0 BMP 0 BMP 2 SIP 2 SIP 2 SIP 2 SIP 2 SIP 3 TIP 3 TIP 2 SIP 0 BMP 0 BMP 0 BMP 0 BMP 0 BMP 0 BMP 0 BMP 0 BMP 0 BMP 1 SMP 2 SIP
4E00–9FFF 3400–4DBF 20000–2A6DF 2A700–2B73F 2B740–2B81F 2B820–2CEAF 2CEB0–2EBEF 30000–3134F 31350–323AF 2EBF0–2EE5F 2E80–2EFF 2F00–2FDF 2FF0–2FFF 3000–303F 31C0–31EF 3200–32FF 3300–33FF F900–FAFF FE30–FE4F 1F200–1F2FF 2F800–2FA1F
20,992 6,592 42,720 4,154 222 5,762 7,473 4,939 4,192 622 115 214 16 64 39 255 256 472 32 64 542
Unified Unified Unified Unified Unified Unified Unified Unified Unified Unified Not unified Not unified Not unified Not unified Not unified Not unified Not unified 12 are unified Not unified Not unified Not unified
Han Han Han Han Han Han Han Han Han Han Han Han Common Han, Hangul, Common, Inherited Common Hangul, Katakana, Common Katakana, Common Han Common Hiragana, Common Han