For much of its history, China was the all-dominant country in East Asia and international relations in this part of the world were more than anything organized by the Chinese and on Chinese terms. China itself was an empire, meaning that the country contained a multitude of different ethnic groups, but the international system of which China was the center concerned the external relations of the empire — its relations with the rest of East Asia. In order to describe these relations the metaphor of a solar system is sometimes used. Here China is the sun around which other and far smaller political entities, located at increasing distances from the center, are circulating in their respective orbits. Some historians use the term “suzerainty,” referring to a relationship in which “a dominant state has control over the international affairs of a subservient state while the latter retains domestic autonomy.” Yet there was a great difference in the way the Chinese dealt with neighbors to the north and the west of the country, and neighbors located predominantly to the south and the east. The former relations were organized according to what we will call the “overland system,” and the latter relations according to what we will call the “tribute system.” There were overlaps between these two systems to be sure and together we can refer to them as the Sino-centric international system, the international system with China at its center.

With rulers and peoples to the north and the west, the Chinese always had a troubled relationship. This was the case for the simple reason that they shared a common border and since these neighbors always constituted a military threat. China was not only exceedingly rich but also difficult to defend militarily, and for that reason alone it constituted a temptation to its neighbors on the steppes of Central Asia. The Chinese empire was periodically overrun by these unruly tribes which, despite their economic and technological inferiority, had access to the most advanced military technology of the day ― bows and arrows and fast horses. The policies which the imperial authorities pursued in return were often defensive: they built walls around their cities and around the northern part of the country as a whole. Yet, on occasion the imperial authorities went on the offensive. The emperors of several dynasties – including the Han, the Tang and the Qing – conducted large-scale military operations against the nomads which took them far into the heart of Central Asia.

But there were limits to both strategies. Defensive strategies did not work once the nomads learned the secrets of siege warfare and once they were able to scale, or simply blow up, the walls that the Chinese had constructed. The offensive strategies did not work since the nomads often preferred to retreat across the steppe rather than to stay put and fight. Such an illusive enemy was impossible to conclusively defeat. In practice the Chinese authorities would instead opt for rather more make-shift solutions and seek to include the nomads in shared institutional arrangements of various kinds. This included exchanges of gifts, marriage alliances, negotiations and diplomatic practices, but also military pacts. Yet these strategies too would often fail, and as a result China was periodically invaded, and taken over, in whole or in parts. Several Chinese dynasties were originally established by tribes coming from the north and the west, including the Yuan, 1271–1368 CE, which was of Mongol origin, and the last imperial dynasty, the Qing, 1644-1911 CE, which was Manchu.

As far as China’s relations with countries to the east and the south were concerned, they were far easier to manage. China’s borders in these directions were shorter and easier to defend, and since communications took place mainly across the sea there was no risk of attacks by ferocious, bow-wielding, horsemen. From these states the Chinese emperors demanded tributes. That is, the foreigners were required to make the journey to the Chinese capital at regular intervals and present gifts to the emperor. These journeys were organized according to a set protocol which included a number of separate rituals, but the highlight of the journey was the audience with the emperor himself. Here the visitors affirmed their loyalty to the empire while the emperor assured them that they indeed were the subjects of his benevolent care. In this way the Chinese were confirmed in their view of themselves — they really were the “Middle Kingdom” to which people from around the world paid tribute. But the foreigners gained something too. The diplomats who showed up in Beijing were recognized as legitimate by the emperor of China and thereby the rulers of their countries were recognized as legitimate too. Besides, while making the journey to China the foreigners always took the opportunity to engage in trade, and trade with China was always highly profitable. The tribute system, as most foreigners saw it, was above all a way to get access to the Chinese market.