China's Boundary and Population

China's land boundary is about 22,000 kilometers long, with a coastline of more than 18,400 kilometers, and another 14,000 kilometers of island shores. According to the Declaration of the People's Republic of China on the Territorial Sea of September 4, 1958, the breadth of China's territorial sea is 12 nautical miles.

After 1840, the imperialist powers successively partitioned China. Since then, China's territory has been divided, leaving behind many boundary problems involving China's sovereignty and fundamental interests. These problems are highlighted in the Sino-Russian border, the Sino-Indian border, the Sino-Vietnamese border, and the maritime and geographic frontiers.

Ancient Boundaries

In ancient times, the ancestors of the Chinese people lived mainly in the middle and lower reaches of the Yellow River, i.e., in the Central Plains. In their neighborhood, they were surrounded by other tribes, known as the Rongdi (戎狄). Legend has it that during the Yellow Emperor's time, attempts were made to divide the countryside into states and set up ten thousand kingdoms, which is certainly absurd, but it also shows that the people at that time already had the concept of boundaries. The history before the Xia Dynasty, due to the lack of documents at that time, only the legend and the record of the later generations as a basis.

According to legend, during the time when Yu was living in China, floods were widespread and he was ordered to treat the water, which took him thirteen years, during which time he "passed through the door of his house three times without entering it", and finally succeeded in treating the water. According to later history, Yu traveled all over the world in the process of curing the water, and made nine states.

The nine states recorded in Yugong, a book written during the Warring States period, is the earliest documented record of China's boundaries. Although it was not written at the time of Yu, it reflects the world view and geography of the Warring States period. It divides China into nine states: Hebei, Yanzhou, Xuzhou, Qingzhou, Yuzhou, Yongzhou, Liangzhou, Jingzhou and Yangzhou.