Kangxi radical

Statistics

The Kangxi dictionary lists a total of 47,035 characters divided among the 214 radicals, for an average of 220 characters per radical, but distribution is unequal, the median number of characters per radical being 64, with a maximum number of 1,902 characters (for radical 140 艸) and a minimum number of five (radical 138 艮). The radicals have between one and seventeen strokes, the median number of strokes being 5 while the average number of strokes is slightly below 5.7.

The ten radicals with the largest number of characters account for 10,665 characters (or 23% of the dictionary). The same ten radicals account for 7,141 out of 20,992 characters (34%) in the Unicode CJK Unified Ideographs block as introduced in 1992, as follows:

Modern dictionaries

Modern Chinese dictionaries continue to use the Kangxi radical-stroke order, both in traditional zidian (字典, lit. "character/logograph dictionary") for written Chinese characters and modern cidian (辭典 "word/phrase dictionary") for spoken expressions. The 214 Kangxi radicals act as a de facto standard, which may not be duplicated exactly in every Chinese dictionary, but which few dictionary compilers can afford to completely ignore. They also serve as the basis for many computer encoding systems, including Unihan. The number of radicals may be reduced in modern practical dictionaries, as some of the more obscure Kangxi radicals do not form any characters that remain in frequent use. Thus, the Oxford Concise English–Chinese Dictionary (ISBN 0-19-596457-8), for example, has 188 radicals. The Xinhua Zidian, a pocket-sized character dictionary containing about 13,000 characters, uses 189 radicals. A few dictionaries also introduce new radicals, treating groups of radicals that are used together in many different characters as a kind of radical. For example, Hanyu Da Cidian, the most inclusive available Chinese dictionary (published in 1993) has 23,000 head character entries organised by a novel system of 200 radicals.

Unicode

The Unicode standard encoded 20,992 characters in version 1.0.1 (1992) in the CJK Unified Ideographs block (U+4E00–9FFF). This standard followed the Kangxi order of radicals (radical 1 at U+4E00, radical 214 at U+9FA0) but did not encode all characters found in the Kangxi dictionary. Individual characters were listed based on their Kangxi radical and number of additional strokes, e.g. U+5382 厂, the unaugmented radical 27 meaning "cliff" is listed under "27.0", while U+5383 to U+5386 are listed under "27.2" as they all consist of radical 27 plus two additional strokes. More characters were added in later versions, adding "CJK Unified Ideographs Extensions" A, B, C and D as of Unicode 7.0 (2014) with further additions planned for Unicode 8.0. Within each "Extension", characters are also ordered by Kangxi radical and additional strokes. The Unicode Consortium maintains the "Unihan Database", with a Radical-Stroke-Index. The Unicode Common Locale Data Repository provides no official collation (sort order) rule for Unicode CJK characters (short of sorting characters by codepoint); such collation rules as there are language-specific (such as JIS X 0208 for Japanese kanji) and do not include any of the CJK Unified Ideographs Extension characters.

Kangxi Radicals block

In Unicode version 3.0 (1999), a separate Kangxi Radicals block was introduced which encodes the 214 radicals in sequence, at U+2F00–2FD5. These are specific codepoints intended to represent the radical qua radical, as opposed to the character consisting of the unaugmented radical; thus, U+2F00 represents radical 1 while U+4E00 represents the character yī meaning "one". In addition, the CJK Radicals Supplement block (2E80–2EFF) was introduced, encoding alternative (often positional) forms taken by Kangxi radicals as they appear within specific characters. For example, ⺁ "CJK RADICAL CLIFF" (U+2E81) is a variant of ⼚ radical 27 (U+2F1A), itself identical in shape to the character consisting of unaugmented radical 27, 厂 "cliff" (U+5382).