How did paiza passports protect merchants in the Mongol Empire?

During the Pax Mongolica, the Mongol empire issued official passports known as paiza (or geregee) to facilitate safer travel and commerce across Eurasia.12

These documents functioned as a form of imperial credential that granted merchants and official travelers significant protections and privileges. By carrying a paiza, merchants were recognized as being under the authority and protection of the Mongol state, which helped shield them from the banditry, arbitrary taxation, and political instability that had previously plagued the Silk Road network.12

In addition to providing security, these passports allowed travelers to utilize the yam, an extensive network of postal and supply stations. At these stations, official couriers and authorized travelers could exchange horses and access resources, enabling them to move across the empire with remarkable speed and efficiency. This system of state-backed security and infrastructure was central to the economic integration and unprecedented level of safety that characterized the Mongol era.12