III. The Initiation of the Maritime Trade System in the Tang Dynasty

Since the Han dynasty, rulers had customarily set up special offices to monopolize and control essential industries of everyday life and profitability, such as the salt industry and iron smelting. Nevertheless, foreign trade was not effectively controlled. On one hand, there were too many corrupted officials who pocketed huge sums of money from foreign trade;on the other hand, local powers seized a majority of foreign trade revenue. "The heads of Lingnan had power over the area because of the richness of population, jades, pearls and rhinoceros horns. Therefore the royal court deployed officers to take the profit from them." In the Tang dynasty, the local tyrants lost their power, and the court fastened its control over foreign trade by setting up a Maritime Trade Superintendent's Office and sending officials under the direct supervision of the emperor to take direct control of it. Hence the Shi Bo System (Maritime Trade System) was born in Guangzhou.

Maritime Trade Superintendent was first recorded in 714, the 2nd year of Kaiyuan. In that year, an official, Zhou Qingli, and Ji Lie, a Persian monk, offered many wonderful rarities to the court. In 722, the 10th year of Kaiyuan, a eunuch whose surname was Wei was posted as the Maritime Trade Superintendent of Guangzhou. Later, five other Maritime Trade Superintendents were recorded in history books, and all of them were in Guangzhou, indicating the important role that Guangzhou played in foreign trade.

Maritime Trade Superintendent in the Tang dynasty was the senior official for managing overseas trade for the purpose of strengthening the government's control over foreign trade, which was occupied by eunuchs or by local military officials; the Superintendent was mainly responsible for purchasing foreign goods, taking charge of the trade tariffs imposed on foreign states, and presided over the management of maritime trade including registration of imported goods and import duty. Though this new system, dually headed by the Maritime Trade Superintendent and local officials was far from mature in the Tang dynasty, it established a framework for overseas trade management that was later adopted by the Song, Yuan and Ming dynasties.