The last of the northern dynasties, the Northern Chou, had been brought to an end by Yang Chien: rapid campaigns had made an end of the remaining petty states, and thus the Sui dynasty had come into power. China, reunited after 360 years, was again under Chinese rule. This event brought about a new epoch in the history of the Far East. But the happenings of 360 years could not be wiped out by a change of dynasty. The short Sui period can only be described as a period of transition to unified forms.
In the last resort the union of the various parts of China proceeded from the north. The north had always, beyond question, been militarily superior, because its ruling class had consisted of warlike peoples. Yet it was not a northerner who had united China but a Chinese though, owing to mixed marriages, he was certainly not entirely unrelated to the northern peoples. The rule, however, of the actual northern peoples was at an end. The start of the Sui dynasty, while the Chou still held the north, was evidence, just like the emergence in the north-east some thirty years earlier of the Northern Ch'i dynasty, that the Chinese gentry with their landowning basis had gained the upper hand over the warrior nomads.
The Chinese gentry had not come unchanged out of that struggle. Culturally they had taken over many things from the foreigners, beginning with music and the style of their clothing, in which they had entirely adopted the northern pattern, and including other elements of daily life. Among the gentry were now many formerly alien families who had gradually become entirely Chinese. On the other hand, the foreigners' feudal outlook had influenced the gentry, so that a sense of distinctions of rank had developed among them. There were Chinese families who regarded themselves as superior to the rest, just as had been the case among the northern peoples, and who married only among themselves or with the ruling house and not with ordinary families of the gentry. They paid great attention to their genealogies, had the state keep records of them and insisted that the dynastic histories mentioned their families and their main family members. Lists of prominent gentry families were set up which mentioned the home of each clan, so that pretenders could easily be detected. The rules of giving personal names were changed so that it became possible to identify a person's genealogical position within the family. At the same time the contempt of the military underwent modification; the gentry were even ready to take over high military posts, and also to profit by them.
The new Sui empire found itself faced with many difficulties. During the three and a half centuries of division, north and south had developed in different ways. They no longer spoke the same language in everyday life (we distinguish to this day between a Nanking and Peking "High Chinese", to say nothing of dialects). The social and economic structures were very different in the two parts of the country. How could unity be restored in these things?
Then there was the problem of population. The north-eastern plain had always been thickly populated; it had early come under Toba rule and had been able to develop further. The region round the old northern capital Ch'ang-an, on the other hand, had suffered greatly from the struggles before the Toba period and had never entirely recovered. Meanwhile, in the south the population had greatly increased in the region north of Nanking, while the regions south of the Yangtze and the upper Yangtze valley were more thinly peopled. The real South, i.e. the modern provinces of Fukien, Kwangtung and Kwangsi, was still underdeveloped, mainly because of the malaria there. In the matter of population the north unquestionably remained prominent.
The founder of the Sui dynasty, known by his reign name of Wen Ti (589-604), came from the west, close to Ch'ang-an. There he and his following had their extensive domains. Owing to the scanty population there and the resulting shortage of agricultural labourers, these properties were very much less productive than the small properties in the north-east. This state of things was well known in the south, and it was expected, with good reason, that the government would try to transfer parts of the population to the north-west, in order to settle a peasantry round the capital for the support of its greatly increasing staff of officials, and to satisfy the gentry of the region. This produced several revolts in the south.
As an old soldier who had long been a subject of the Toba, Wen Ti had no great understanding of theory: he was a practical man. He was anti-intellectual and emotionally attached to Buddhism; he opposed Confucianism for emotional reasons and believed that it could give him no serviceable officials of the sort he wanted. He demanded from his officials the same obedience and sense of duty as from his soldiers; and he was above all thrifty, almost miserly, because he realized that the finances of his state could only be brought into order by the greatest exertions. The budget had to be drawn up for the vast territory of the empire without any possibility of saying in advance whether the revenues would come in and whether the transport of dues to the capital would function.
This cautious calculation was entirely justified, but it aroused great opposition. Both east and south were used to a much better style of living; yet the gentry of both regions were now required to cut down their consumption. On top of this they were excluded from the conduct of political affairs. In the past, under the Northern Ch'i empire in the north-east and under the Ch'en empire in the south, there had been thousands of positions at court in which the whole of the gentry could find accommodation of some kind. Now the central government was far in the west, and other people were its administrators. In the past the gentry had a profitable and easily accessible market for their produce in the neighbouring capital; now the capital was far away, entailing long-distance transport at heavy risk with little profit.
The dissatisfied circles of the gentry in the north-east and in the south incited Prince Kuang to rebellion. The prince and his followers murdered the emperor and set aside the heir-apparent; and Kuang came to the throne, assuming the name of Yang Ti. His first act was to transfer the capital back to the east, to Loyang, close to the grain-producing regions. His second achievement was to order the construction of great canals, to facilitate the transport of grain to the capital and to provide a valuable new market for the producers in the north-east and the south. It was at this time that the first forerunner of the famous "Imperial Canal" was constructed, the canal that connects the Yangtze with the Yellow River. Small canals, connecting various streams, had long been in existence, so that it was possible to travel from north to south by water, but these canals were not deep enough or broad enough to take large freight barges. There are records of lighters of 500 and even 800 tons capacity! These are dimensions unheard of in the West in those times. In addition to a serviceable canal to the south, Yang Ti made another that went north almost to the present Peking.
Hand in hand with these successes of the north-eastern and southern gentry went strong support for Confucianism, and a reorganization of the Confucian examination system. As a rule, however, the examinations were circumvented as an unimportant formality; the various governors were ordered each to send annually to the capital three men with the required education, for whose quality they were held personally responsible; merchants and artisans were expressly excluded.