China proper, Inner China or the Eighteen Provinces was a term used by Western writers on the Manchu Qing dynasty to express a distinction between the core and frontier regions of China. There is no fixed extent for China proper, as many administrative, cultural, and linguistic shifts have occurred in Chinese history. One definition refers to the original area of Chinese civilization, the Central Plain (in the North China Plain); another to the "Eighteen Provinces" system of the Qing dynasty. There is no direct translation for "China proper" in the Chinese language due to differences in terminology used by the Qing to refer to the regions and the expression is controversial among scholars, particularly in China, due to national territorial claims.
It is not clear when the concept of "China proper" in the Western world appeared. However, it is plausible that historians during the age of empires and the fast-changing borders in the eighteenth century, applied it to distinguish China's 18-provinces from its newly acquired properties. This would also apply to Great Britain proper versus the British Empire, which would encompass vast lands overseas. The same would apply to France proper in contrast to the French Empire of the time, which Napoleon managed to expand all the way to Moscow.
According to Harry Harding, the concept can date back to 1827. But as early as in 1795, William Winterbotham adopted this concept in his book. When describing the Chinese Empire under the Qing dynasty, Winterbotham divided it into three parts: China proper, Chinese Tartary, and the States Tributary to China. He adopted the opinions of Du Halde and Grosier and suspected that the name of "China" came from Qin dynasty. He then said: "China, properly so called,... comprehends from north to south eighteen degrees; its extent from east to west being somewhat less..."
However, to introduce China proper, Winterbotham still used the outdated 15-province system of the Ming dynasty, which the Qing dynasty used until 1662. Although Ming dynasty also had 15 basic local divisions, Winterbotham uses the name of Kiang-nan (江南, Jiāngnán) province, which had been called Nan-Zhili (南直隶, Nán-Zhílì) during the Ming dynasty and was renamed to Kiang-nan (i.e., Jiangnan) in 1645, the second year after the Manchu Qing dynasty overthrew the Ming. This 15-province system was gradually replaced by the 18-province system between 1662 and 1667. Using the 15-province system and the name of Kiang-nan Province indicates that the concept of China proper probably had appeared between 1645 and 1662 and this concept may reflect the idea that identifies China as the territory of the former Ming dynasty after the Qing conquest of the Ming.
The concept of "China proper" also appeared before this 1795 book. It can be found in The Gentleman's Magazine, published in 1790, and The Monthly Review, published in 1749. In the nineteenth century, the term "China proper" was sometimes used by Chinese officials when they were communicating in foreign languages. For instance, the Qing ambassador to Britain Zeng Jize used it in an English language article, which he published in 1887.
Dulimbai Gurun is the Manchu name for China (中國, Zhongguo; "Middle Kingdom"). After conquering the Ming, the Manchu Qing identified their state as "China" (Zhongguo), and referred to it as "Dulimbai Gurun" in Manchu. The Manchu Qing Emperors equated the lands of the Qing state (including both "China proper" and present day Manchuria, Xinjiang, Mongolia, Tibet and other areas as "China" in both the Chinese and Manchu languages, defining China as a multi ethnic state, rejecting the idea that China only meant Han areas in "China proper", proclaiming that both Han and non-Han peoples were part of "China", using "China" to refer to the Qing in official documents, international treaties, and foreign affairs, and the "Chinese language" (Dulimbai gurun i bithe) referred to Chinese, Manchu, and Mongol languages, and the term "Chinese people" (中國人, Zhongguo ren; Manchu: Dulimbai gurun i niyalma) referred to all Han, Manchus, and Mongol subjects of the Qing.
When the Qing conquered Dzungaria in 1759, they proclaimed that the new land was absorbed into "China" (Dulimbai Gurun) in a Manchu language memorial. The Qing expounded on their ideology that they were bringing together the "outer" non-Han Chinese like the Inner Mongols, Eastern Mongols, Oirat Mongols, and Tibetans together with the "inner" Han Chinese, into "one family" united in the Qing state, showing that the diverse subjects of the Qing were all part of one family, the Qing used the phrase "Zhong Wai Yi Jia" (中外一家) or "Nei Wai Yi Jia" (內外一家, "interior and exterior as one family"), to convey this idea of "unification" of the different peoples. A Manchu language version of a treaty with the Russian Empire concerning criminal jurisdiction over bandits called people from the Qing as "people of the Central Kingdom (Dulimbai Gurun)" 
In the Manchu official Tulisen's Manchu language account of his meeting with the Torghut Mongol leader Ayuki Khan, it was mentioned that while the Torghuts were unlike the Russians, the "people of the Central Kingdom" (dulimba-i gurun; 中國, Zhongguo) were like the Torghut Mongols, and the "people of the Central Kingdom" referred to the Manchus.
While the Manchu Qing sought used China (Zhongguo) to describe non-Han areas, however some Han scholar-officials opposed the Qing Manchu Emperor's use of Zhongguo to refer to non-Han areas, using Zhongguo to mark a distinction between the culturally Han Chinese areas and the territory newly brought into the Manchu Qing empire. In the early 19th century, Wei Yuan’s Shengwuji (Military History of the Qing Dynasty) calls the inner Asian polities guo, while the seventeen provinces of the traditional heartland, that is, "China proper," and three eastern provinces of Manchuria are called "Zhongguo." Some Han Chinese Ming loyalists refused to use Zhongguo to refer to areas outside the borders of the Ming Empire such as outer Mongolia, in effect refusing to acknowledge the Qing state.
The Manchu Qing referred to the Han Chinese inhabited 18 provinces as "nèidì shíbā shěng" (內地十八省), which meant the "interior region eighteen provinces", or abbreviated it as "nèidì" (內地), "interior region" and also as "jùnxiàn" (郡县), while they referred to the non-Han areas of China such as the Northeast, Outer Mongolia, Inner Mongolia, Xinjiang, and Tibet as "wàifān" (外藩) which means "outer feudatories" or "outer vassals", or as "fānbù" (藩部, "feudatory region"). These waifan were fully subjected to and governed by the Qing government and were considered part of the China (Zhongguo), unlike wàiguó (外國, "outer/foreign countries") like Korea, Vietnam, and the Ryukyus, who paid tribute to the Qing but were not part of China.
In the early 20th century, series of Sino-Japanese conflict had raised Chinese people's concern for national unity, and the concept of a unified, undivided Chinese nation became more popular among Chinese scholars. On Jan 1, 1939, Gu Jiegang published his article "The term 'China proper' should be abolished immediately", which argued that the widely accepted area covered by "China proper" is not the actual territory of any of the Chinese dynasties. Gu further theorized that "中国本部", the Chinese and Japanese term equal to "China proper" at the time, actually originated from Japan and was translated into "China proper", hence the concept of "China proper" was developed by Japanese people, and it had become a tool to divide Chinese people, making way for Japanese invasion of Mongolia, Manchuria, and all parts of China. Gu's article sparked a heated debate on the definition and origin of "Zhonghua minzu", which contributed to unifying Chinese people in the Second Sino-Japanese war, and to an extent shaped the later established concept of Zhonghua minzu.
Today, China proper is a controversial concept in China itself, since the current official paradigm does not contrast the core and the periphery of China. There is no single widely used term corresponding to it in the Mandarin language.
The separation of China into a "China proper" dominated by Han Chinese and one or more "Other Chinas" of ethnic minorities impugns on the legitimacy of China's current borders, which is based on the succession of states principle. According to Sinologist Colin Mackerras, foreign governments have generally accepted Chinese claims over its minority areas, because to redefine a country's territory every time it underwent a change of regime would cause endless instability and warfare. Also, he asks, "if the boundaries of the Qing were considered illegitimate, why should it go back to the much smaller Ming in preference to the quite extensive Tang dynasty boundaries?"
There is no fixed extent for China proper, as it is used to express the contrast between the core and frontier regions of China from multiple perspectives: historical, administrative, cultural, and linguistic.
One way of thinking about China proper is to refer to ancient Han Chinese dynasties. Chinese civilization developed from a core region in the North China Plain, and expanded outwards over several millennia, conquering and assimilating surrounding peoples, or being conquered and influenced in turn. Some dynasties, such as the Han and Tang dynasties, were particularly expansionist, extending far into Central Asia, while others, such as the Jin and Song dynasties, were forced to relinquish the North China Plain itself to rivals from Northeastern and Central Asia.
The Ming Dynasty was the last Han Chinese dynasty and second-last imperial dynasty to rule China. It governed fifteen administrative entities, which included thirteen provinces (Chinese: 布政使司; pinyin: Bùzhèngshǐ Sī) and two "directly-governed" areas. After the Manchu-founded Qing Dynasty succeeded the Ming Dynasty, the Qing court decided to continue to use the Ming administrative system to rule over former Ming lands, without applying it to other domains within the Qing Dynasty, namely Manchuria, Mongolia, Xinjiang, and Tibet. The 15 administrative units of the Ming Dynasty underwent minor reforms to become the Eighteen Provinces (一十八行省; Yīshíbā Xíngshěng, or 十八省; Shíbā Shěng) of China proper under the Qing Dynasty. It was these eighteen provinces that early Western sources referred to as China proper.
There are some minor differences between the extent of Ming China and the extent of the eighteen provinces of Qing China: for example, some parts of Manchuria were a Ming possession belonging to the Ming province of Liaodong (now Liaoning); however, the Qing conquered it before the rest of China and did not put the region back into the provinces of China proper. On the other hand, Taiwan was a new acquisition of the Qing Dynasty, and it was put into Fujian, one of the provinces of China proper. Eastern Kham in Greater Tibet was added to Sichuan, while much of what now constitutes northern Burma was added to Yunnan.
Near the end of the Qing Dynasty, there was an effort to extend the province system of China proper to the rest of the empire. Taiwan was made into a separate province in 1885, but was ceded to Japan in 1895. Xinjiang was reorganized into a province in 1884. Manchuria was split into the three provinces of Fengtian, Jilin and Heilongjiang in 1907. There was discussion to do the same in Tibet, Kokonor, Inner Mongolia, and Outer Mongolia, but these proposals were not put to practice, and these areas were outside the province system of China proper when the Qing Dynasty fell in 1912.
Some of the revolutionaries who sought to overthrow Qing rule desired to establish a state independent of the Qing Dynasty within the bounds of the Eighteen Provinces, as evinced by the Eighteen-Star Flag they used. Others favoured the replacement of the entire Qing Dynasty by a new republic, as evinced by the Five-Striped Flag they used. Some revolutionaries, such as Zou Rong, used the term Zhongguo Benbu (中国本部) which roughly identifies the Eighteen Provinces. When the Qing Dynasty fell, the abdication decree of the Qing Emperor bequeathed the entire Empire to the newborn Republic of China, and the latter idea was therefore adopted by the new republic as the principle of Five Races Under One Union, with Five Races referring to the Han Chinese, Manchus, Mongols, Muslims (Uyghurs, Hui etc.) and Tibetans. The Five-Striped Flag was adopted as the national flag, and the Republic of China viewed itself as a single state encompassing all five regions handed down by the Qing Dynasty. The People's Republic of China, which was founded in 1949 and replaced the Republic of China on the mainland, has continued to claim essentially the same borders, with the only major exception being the recognition of independent Mongolia. As a result, the concept of China proper fell out of favour in China.
The Eighteen Provinces of the Qing Dynasty still exist, but their boundaries have changed. Beijing and Tianjin were eventually split from Hebei (renamed from Zhili), Shanghai from Jiangsu, Chongqing from Sichuan, Ningxia autonomous region from Gansu, and Hainan from Guangdong. Guangxi is now an autonomous region. The provinces that the late Qing dynasty set up have also been kept: Xinjiang became an autonomous region under the People's Republic of China, while the three provinces of Manchuria now have somewhat different borders, with Fengtian renamed as Liaoning.
When the Qing Dynasty fell, Republican Chinese control of Qing territory, including of those generally considered to be in "China proper", was tenuous, and practically nonexistent in Tibet and Outer Mongolia (since 1922), which were controlled by governments that declared independence. The Republic of China subdivided Inner Mongolia in its time on the mainland, although the People's Republic of China later joined Mongol-inhabited territory into a single autonomous region. The PRC joined the Qamdo area into the Tibet area (later the Tibet Autonomous Region). Nationalist China was forced to acknowledge the independence of Mongolia (former Outer Mongolia) and Tannu Uriankhai (now part of Russia as The Tyva Republic), in 1945.
China proper is often associated with the Han Chinese, the majority ethnic group of China and with the extent of the Chinese languages, an important unifying element of the Han Chinese ethnicity.
However, Han Chinese areas in the present day do not correspond well to the Eighteen Provinces of the Qing Dynasty. Much of southwestern China, such as areas in the provinces of Yunnan, Guangxi, and Guizhou, was part of successive Han Chinese dynasties, including the Ming Dynasty and the Eighteen Provinces of the Qing Dynasty. However, these areas were and continue to be populated by various non-Han Chinese minority groups, such as the Zhuang, the Miao people, and the Bouyei. Conversely, today Han Chinese form the majority in most of Manchuria, much of Inner Mongolia, many areas in Xinjiang and scattered parts of Tibet, not least due to the expansion of Han Chinese settlement encouraged by the late Qing dynasty, the Republic of China, and the People's Republic of China.
Ethnic Han Chinese is not synonymous with speakers of the Chinese language. Many non-Han Chinese ethnicities, such as the Hui and Manchu, are essentially monolingual in Chinese, but do not identify as Han Chinese. The Chinese language itself is also a complex entity, and should be described as a family of related languages rather than a single language if the criterion of mutual intelligibility is used to classify its subdivisions.
In polls a slim majority of the people of Taiwan call themselves "Taiwanese" only with the rest identifying as "Taiwanese and Chinese" or "Chinese" only. 98% of the people of Taiwan are descendants of immigrants from China since the 1600s, but the inclusion of Taiwan in China, or in the China proper, is still a controversial subject. See History of Taiwan and Political status of Taiwan for more information.