Kangxi radical

The 214 Kangxi radicals, also known as Zihui radicals, were collated in the 18th-century Kangxi Dictionary to aid categorization of Chinese characters. They are primarily sorted by stroke count. They are the most popular system of radicals for dictionaries that order characters by radical and stroke count. They are encoded in Unicode alongside other CJK characters, under the block "Kangxi radicals", while graphical variants are included with in the "CJK Radicals Supplement".

Originally introduced in the 1615 Zihui, they are more commonly referred to in relation to the 1716 Kangxi Dictionary—Kangxi being the commissioning emperor's era name. The 1915 encyclopedic word dictionary Ciyuan also uses this system. In modern times, many dictionaries that list Traditional Chinese head characters continue to use this system. For example, the Wang Li Character Dictionary of Ancient Chinese (2000) adopted the Kangxi radicals system. The system of 214 Kangxi radicals is based on the older system of 540 radicals used in the Han-era Shuowen Jiezi. Since 2009, the Chinese Government has promoted a 201-radical system (Table of Han Character Radicals) called the Table of Indexing Chinese Character Components, as a national standard for use with simplified character forms.

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 zìdiǎn (, lit. "character/logograph dictionary") for written Chinese characters and modern cídiǎn ( "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. 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, for example, has 188 radicals. The Xinhua Zidian, a pocket-sized character dictionary containing about 13,000 characters, uses 189 radicals, later (10th ed.) increased to 201 to conform to a national standard. 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.

In Unicode
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 code points 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).