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.
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.
Also in CJK Unified Ideographs Extension B, hundreds of glyph variants were encoded.