1. In the early years of the Han Dynasty, the lessons of the demise of the Qin Dynasty were learned. In order to communicate local commodities, invigorate the market and promote economic development, no tariffs were imposed.

2. After Zhang Qian went to the Western Regions, the foreign trade between the Han Dynasty and the Western Regions flourished. The Western Han Dynasty added many passes and checkpoints in inland and border areas, and began to levy tariffs.