Although many radicals that we are using in modern time were all originated in ancient period, the written forms of the modern radicals differ dramatically from that of the ancient time. This is due to the historical evolution of Chinese scripts. Same as the evolution of Chinese characters, the Chinese radicals has undergone five-stage development in their written forms: Oracle bone inscription, bronze vessel inscription, seal style, official style, and regular style. From bronze vessel inscription to seal style, we refer to them as ancient scripts as they still remain the pictographic shape although the changes in the structure are obvious. We refer to the official and regular styles as modern scripts as the strokes in these two styles are no longer curved rather they are straitened, which diminishes the pictographic characteristics of the script.Therefore, modern Chinese script is not a pictographic writing, rather, they are abstract symbols composed by strokes. Below illustrates historical evolution of radical目.      

甲骨文 Oracle Bone Inscription：

金文 Bronze Vessel Inscription：

小篆 Small Seal Style：

隸書 Official Style：目

楷書 Regular Style：目

Chinese writing originated from pictographs. If we trace down the origin of each radical, we will find that they were pictures of objects. This is the reason that Chinese characters have obvious meaning-script correspondence. Take the above mentioned radical目as an example, by looking at its oracle bone inscription, we can tell the meaning of 目is “eye.” Below is another example. After viewing the following three pictures, you may have well guessed the meaning of the radical犬, which is dog; the radical犬 was created by drawing a picture of dog. 

The historical evolution of the physical structure of the radical犬is illustrated below:

甲骨文Oracle Bone Inscription：

金文Bronze Vessel Inscription：

小篆Small Seal Style：

隸書Official Style：   犬  

楷書Regular Style：  犬

From the oracle bone inscription, we can tell the head of the 犬is upward but the tail is downward. The two legs are a bit leftward. Since in the reality, the tail of a dog often rolls upward, this feature is even more noticeable in the two images of bronze inscription. In the small seal style and regular script, the pictographic feature is obscured and we can no longer tell that犬 resembles a dog. If, however，we equipped ourselves with the knowledge of the historical changes of the written forms of radicals, certainly it will be much easier for us to memorize the shape and meaning of the modern form of radicals. Here are a few more examples: radial山 means mountain and its pictographic form depicts mountain peaks （ ）; radical水 means water and its pictographic form resembles to flowing water(); radical日means sun and its pictographic form looks like a round sun (); and radical人 means person and its pictographic form looks like a profile of a person ().

When radicals are used to form a compound character, they can be placed in the different positions in a compound character. A radical often is given an alternative version in order to fit in the square block shape of the compound character. We refer to those radicals remaining the original shape in a compound character as “regular version”, and those with certain changes as “alternative version.” The regular and alternative versions of radicals only differ in the shape but not in the meaning and sound they represent. For example, the alternative version for 犬 is 犭. 犬 in 哭 remains as its regular version, but it appears in 狗 as an alternative version standing in the left side of the compound character. The radical 心 means heart which can form a compound character such as思. 心 has two alternative versions忄and , and they form compound characters like情 and 慕.

In 1950s, the government of the Peoples Republic of China promoted simplification of Chinese characters, more than two thousands of high frequency characters are simplified in strokes. Consequently, some radicals as integral characters were also simplified. To cite an example, the compound character 餠 has its simplified version of 饼. The radical飠in the left part of character is written as饣.

Some radicals in ancient time were created based on exiting radicals. For example, radical甘（），  which means sweet, was created by adding a horizontal stroke to the exiting radical口（） .This added stroke is to indicate the taste of sweet by the tongue. Another example is立 （） which means to stand. This radical was created by adding another horizontal stroke underneath of the radical (big) to indicate that a person is standing. Strictly speaking, this type of radicals is no longer pure pictographs but ideographs.

A radical can appear in different positions of a compound character. Below are examples of commonly seen positions that a radical appears in a compound character:

(1) A radical appears in the left-side of a compound character：氵→ 江.

(2) A radical appears in the right-side of a compound character: 攵→ 政.

(3) A radical appears in the middle of a compound character: 口→ 哀.

(4) A radical appears on the top of a compound character: 宀→ 室.

(5) A radical appears at the bottom of a compound character：土→ 塹.

(6) A radical half-encircles another radical or integral character：門→ 闖.

When learn a new compound character, if we can identify a learned radical from the compound character, it will not only help us to learn the shape but also the meaning of the compound character. If, a radical serves as a phonetic cue for a compound character, to identify the radical will also help us learn the sound of the compound character.

By now, we should know that radicals are the orthographic unit forming compound characters. Therefore, once we have learned enough high frequency radicals, when encountering a compound character, we will not consider the character consisting of a pile of random strokes, rather, we consider it a meaningful combination of radicals. For instance, when we see the character古 (ancient), we can tell that it is formed by two radicals, 十 and 口，rather than to say it is formed by a bunch of strokes. The structural relationships among radicals, integral characters, and compound characters can be summarized as follow:

(1)  A radical itself is an integral character: 水.

(2)  A radical is added another stroke to form another integral character: 甘.

(3) Duplicate the same radical to form a compound character: 木 → 林,森.

(4) Combine different radicals to form a compound character: 忄plus 青→ 情.

(5) A radical combine with other integral character to form a compound character: Radical 氵 plus an integral character 可 to form 河.

With this knowledge in our minds, when seeing a new compound character, we should analyze the structure of the new compound and find out how many radicals in the compound and in which position the radicals are placed, it will greatly reduce our memory burden and make learning more effective.

In the above section, we mentioned there are a total of 214 radicals in Chinese. If we would like to memorize all 214 radicals, the best way is to classify these radicals according to the meanings they represent, below are some examples of radical classification based on their meanings:

(1) Human: human, great, son, daughter, body, etc;

(2) Human body: eyes, mouth, tongue, ears, etc;

(3) Animals: cows, horses, sheep, dogs, etc;

（4）Plants: grass, wood, grass, rice, etc;

（5）Astronomy: sun, moon, stars, clouds, rain, etc;

Once you have learned certain number of radicals, you may try to classify radicals based on your own meaning categories. As soon as you have established the taxonomy for the radicals, you can add newly learned radicals to your taxonomy, which will facilitate meaningful memorization of radicals.

Initially, each radical was created to represent only one meaning of an object. We refer to the original meaning of the radical as the basic meaning. Along with the development of Chinese language, one radical later is used to represent several things. That means one radical could have several meanings. However, those later added meanings are related to the basic meaning of the radical. We refer to those meanings which developed based on the basic meaning as extended meanings. For example, the basic meaning for 火 as radical is fire; the compound character煌 with radical火 means glory, the character燥 dry (after baked by a fire). When 火 is used as an integral character, it often can be combined with other characters forming different words or phrases to represent different meanings which still have certain connection with the basic meaning of火. Below are a few examples:

火紅的太陽 (the sun with fire color)

 紅火 (bustle)

火紅的青春 (lively youth)

上火   inflammation

動火   get angry

Once we have known the relationships between basic meaning of a radical and its connection to the extended meanings, it is very helpful for us to memorize the meanings of compound characters that contain the same radical or words and phrases in which the radical is used as integral character. 

The Chinese language develops along with the Chinese society and culture. Naturally, the way how the Chinese characters were created reflects ancient Chinese’ life style, world view, and religious believe; it also reflects the development of the Chinese society such as fine arts, literature, customs and conventions. Radicals as earliest Chinese characters embody Chinese culture and society at the time. For example, radical女, is written as in oracle bone inscription. Observing from its shape, it looks like a woman kneeling down with two hands crossed. From this pictograph, we can infer that at that time, kneeling position may be a common posture for a woman to do work at home. Or perhaps female’s social status was already not high, as kneeling position also indicates a person’s inferior social status. To cite another example, the radical父 () looks like a male holing a stone axe. We can imagine that males were often working outdoor and used stone axe to catch animals, to harvest food, or to attack enemy in order to protect tribe’s safety. We could also infer that China was in the Stone Age at that time. Therefore, learning radicals not only help to learn Chinese characters but also Chinese culture and history as well. 

By now, we hope that you have had a general understanding of why we need to learn Chinese radicals. We certainly hope that by Learning the knowledge of Chinese character radicals, you will use your radical knowledge to acquire more Chinese characters.