In the Kai-huang _??__??_ period of the Sui dynasty (581-618), the lu-zhi _??__??_ had two major divisions: the lu-zhi for the jing-guan _??__??_ and the lu-zhi for the wai-guan _??__??_. There were three principles for determining the amount of lu _??__??_ that the wai-guan received.
Whereas the jing-guan was paid his lu according to his zhi-shipin _??__??__??_, the wai-guan received his lu based on his position in the zhou-jun-xian jiu-deng-zhi _??__??__??__??__??__??_ (essentially a nine-rank system based on the administrative districts of zhou "province", jun "prefecture" and xian "county"). This was the first principle.
As for the second principle, we come to find that the wai-guan had a higher lu than the jing-guan even though their zhi-shi-pin be equal. We can call this wai-guan you-yu _??__??__??__??_, or the "principle of favoring the wai-guan".
In order to prevent the wai-guan from receiving too much lu, however, a third principle was employed to limit the amount. Though the wai-guan received more lu than the jing-guan of the same rank (in the zhi-shi-pin "status" system), he could not receive more than the jing-guan who was two ranks higher. We can call this limitation you-yu xian-ding _??__??__??__??_, or the "principle of limiting the favored".
Though we do not possess documents stating how much lu the chang-shi _??__??_ and si-ma _??__??_ received, we can make close approximations by considering their rank in the zhi-shi-pin system and by applying the three principles we have analysed above.
The Kai-huang period lu-zhi was later reformed and a new lu-zhi for the jing-guan was also established in the Daye _??__??_ period. This lu-zhi continued and was in effect throughout the former half of the Tang dynasty (618-907), though there were some changes. In addition, the lu-zhi for the wai-guan in the Tang dynasty showed great differences from that in the Sui dynasty.
