Kangxi radicals

The Kangxi radicals, also known as Zihui radicals, are a set of 214 radicals that 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 in the block "CJK Radicals Supplement".
Originally introduced in the Zihui dictionary of 1615, 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. The system of 214 Kangxi radicals is based on the older system of List of [Shuowen Jiezi radicals|540 radicals] used in the Han-era Shuowen Jiezi. Since 2009, the Chinese government has promoted a 201-radical system called the Table of Indexing [Chinese Character Components]'', as a national standard for use with simplified characters.

Statistics

The Kangxi dictionary lists a total of 47,035 characters divided among the 214 radicals, for an average of 220 characters per radical; however, the distribution is unequal, with the median number of characters per radical being 64, the maximum number being 1,902, and the minimum being 5. The radicals have between one and 17 strokes, with a median of 5 strokes and an average of slightly below 5.7 strokes.
The ten radicals with the largest number of derived characters account for 10,665 characters. The same ten radicals account for 7,141 out of the 20,992 characters in the Unicode CJK Unified Ideographs block as it was introduced in 1992, as follows:

Radical	Kangxi Dictionary	CJK Unified Ideographs
Radical 140 艸 "grass"	1,902 characters	981 characters
Radical 85 水 "water"	1,595 characters	1,079 characters
Radical 75 木 "tree"	1,369 characters	1,016 characters
Radical 64 手 "hand"	1,203 characters	740 characters
Radical 30 口 "mouth"	1,146 characters	756 characters
Radical 61 心 "heart"	1,115 characters	581 characters
Radical 142 虫 "insect"	1,067 characters	469 characters
Radical 118 竹 "bamboo"	953 characters	378 characters
Radical 149 言 "speech"	861 characters	567 characters
Radical 120 糸 "silk"	823 characters	574 characters

Modern dictionaries

Modern Chinese dictionaries continue to use the Kangxi radical-stroke order, both in traditional for written Chinese characters and modern 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 increased to 201 in its tenth edition, to conform to the 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 has 23,000 head character entries organized by a novel system of 200 radicals.

In Unicode

In Unicode version 3.0, 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 was introduced, encoding alternative forms taken by Kangxi radicals as they appear within specific characters. For example, ⺁ "CJK RADICAL CLIFF" is a variant of ⼚ radical 27, itself identical in shape to the character consisting of unaugmented radical 27, 厂 "cliff".