The complexity of the Chinese writing system is well known. Some of the linguistic factors that contribute to this include the large number of characters in common use, the complexity of the character forms, the major differences between traditional Chinese and simplified Chinese along various dimensions (orthography, phonology, semantics), the presence of numerous orthographic variants in traditional Chinese, and others.
Variant characters refer to a set of characters with the same pronunciation and meaning but different shapes. Since Chinese characters are comprised of meaning signs, phonetic signs and marks, different people in different periods might have chosen different meaning signs from different perspectives and phonetic signs, different from alphabetic letters, do not have uniform forms. As a result, variant characters can be found everywhere in the history of Chinese characters.
Variant Chinese characters can be categorized into six groups – variant characters with different graphic components, variant characters with the same phonetic components such as 
(liang, grain), 
(lian, pity), 
(xiu, embroider), 
(jiao, glue), 
(ku, trousers) and 
(xian, string); variant characters with components in different places; variant characters created differently such as 
(diao, condole), 
(ti, body), and 
(lei, tear); variant characters with a different number of radicals such as 
(pang, mooch), 
(yi, doctor), and
(sheng, sound); and variant characters with different simplicity such as 
(long, dragon), 
(xue, study), 
(tou, head) and 
(dui, right).
In order to facilitate people’s study of Chinese characters, the Ministry of Culture of the People’s Republic of China and the Chinese Characters Reforming Committee jointly published the first batch of variant characters, eliminating 1,055 variant characters.
（Source: chinaculture.org）
