The change of dynasty in the state of Wei did not bring any turn in China's internal history. Ssu-ma Yen, who as emperor was called Wu Ti (265-289), had come to the throne with the aid of his clique and his extraordinarily large and widely ramified family. To these he had to give offices as reward. There began at court once more the same spectacle as in the past, except that princes of the new imperial family now played a greater part than under the Wei dynasty, whose ruling house had consisted of a small family. It was now customary, in spite of the abolition of the feudal system, for the imperial princes to receive large regions to administer, the fiscal revenues of which represented their income. The princes were not, however, to exercise full authority in the style of the former feudal lords: their courts were full of imperial control officials. In the event of war it was their duty to come forward, like other governors, with an army in support of the central government. The various Chin princes succeeded, however, in making other governors, beyond the frontiers of their regions, dependent on them. Also, they collected armies of their own independently of the central government and used those armies to pursue personal policies. The members of the families allied with the ruling house, for their part, did all they could to extend their own power. Thus the first ruler of the dynasty was tossed to and fro between the conflicting interests and was himself powerless. But though intrigue was piled on intrigue, the ruler who, of course, himself had come to the head of the state by means of intrigues, was more watchful than the rulers of the Wei dynasty had been, and by shrewd counter-measures he repeatedly succeeded in playing off one party against another, so that the dynasty remained in power. Numerous widespread and furious risings nevertheless took place, usually led by princes. Thus during this period the history of the dynasty was of an extraordinarily dismal character.

In spite of this, the Chin troops succeeded in overthrowing the second southern state, that of Wu (A.D. 280), and in so restoring the unity of the empire, the Shu Han realm having been already conquered by the Wei. After the destruction of Wu there remained no external enemy that represented a potential danger, so that a general disarmament was decreed (280) in order to restore a healthy economic and financial situation. This disarmament applied, of course, to the troops directly under the orders of the dynasty, namely the troops of the court and the capital and the imperial troops in the provinces. Disarmament could not, however, be carried out in the princes' regions, as the princes declared that they needed personal guards. The dismissal of the troops was accompanied by a decree ordering the surrender of arms. It may be assumed that the government proposed to mint money with the metal of the weapons surrendered, for coin (the old coin of the Wei dynasty) had become very scarce; as we indicated previously, money had largely been replaced by goods so that, for instance, grain and silks were used for the payment of salaries. China, from _c_. 200 A.D. on until the eighth century, remained in a period of such partial "natural economy".

Naturally the decree for the surrender of weapons remained a dead-letter. The discharged soldiers kept their weapons at first and then preferred to sell them. A large part of them was acquired by the Hsiung-nu and the Hsien-pi in the north of China; apparently they usually gave up land in return. In this way many Chinese soldiers, though not all by any means, went as peasants to the regions in the north of China and beyond the frontier. They were glad to do so, for the Hsiung-nu and the Hsien-pi had not the efficient administration and rigid tax collection of the Chinese; and above all, they had no great landowners who could have organized the collection of taxes. For their part, the Hsiung-nu and the Hsien-pi had no reason to regret this immigration of peasants, who could provide them with the farm produce they needed. And at the same time they were receiving from them large quantities of the most modern weapons.

This ineffective disarmament was undoubtedly the most pregnant event of the period of the western Chin dynasty. The measure was intended to save the cost of maintaining the soldiers and to bring them back to the land as peasants (and taxpayers); but the discharged men were not given land by the government. The disarmament achieved nothing, not even the desired increase in the money in circulation; what did happen was that the central government lost all practical power, while the military strength both of the dangerous princes within the country and also of the frontier people was increased. The results of these mistaken measures became evident at once and compelled the government to arm anew.