nate posts were there
specialists, such as jurists, physicians, and so on. A change came
towards the end of the T'ang period, when a Department of Commerce and
Monopolies was set up; only specialists were appointed to it, and it was
placed directly under the emperor. Except for this, any official could
be transferred from any ministry to any other without regard to his
experience.

4 _Turkestan policy. End of the Hsiung-nu empire_

In the two decades between 160 and 140 B.C. there had been further
trouble with the Hsiung-nu, though there was no large-scale fighting.
There was a fundamental change of policy under the next emperor, Wu (or
Wu Ti, 141-86 B.C.). The Chinese entered for the first time upon an
active policy against the Hsiung-nu. There seem to have been several
reasons for this policy, and several objectives. The raids of the
Hsiung-nu from the Ordos region and from northern Shansi had shown
themselves to be a direct menace to the capital and to its extremely
important hinterland. Northern Shansi is mountainous, with deep ravines.
A considerable army on horseback could penetrate some distance to the
south before attracting attention. Northern Shensi and the Ordos region
are steppe country, in which there were very few Chinese settlements and
through which an army of horsemen could advance very quickly. It was
therefore determined to push back the Hsiung-nu far enough to remove
this threat. It was also of importance to break the power of the
Hsiung-nu in the province of Kansu, and to separate them as far as
possible from the Tibetans living in that region, to prevent any union
between those two dangerous adversaries. A third point of importance was
the safeguarding of caravan routes. The state, and especially the
capital, had grown rich through Wen Ti's policy. Goods streamed into the
capital from all quarters. Commerce with central Asia had particularly
increased, bringing the products of the Middle East to China. The
caravan routes passed through western Shensi and Kansu to eastern
Turkestan, but at that time the Hsiung-nu dominated the approaches to
Turkestan and were in a position to divert the trade to themselves or
cut it off. The commerce brought profit not only to the caravan traders,
most of whom were probably foreigners, but to the officials in the
provinces and prefectures through which the routes passed. Thus the
officials in western China were interested in the trade routes being
brought under di