Ortoo

Yam (Mongolian: Өртөө, Örtöö, checkpoint) is a supply point route messenger system employed and extensively used and expanded by Genghis Khan and used by subsequent Great Khans and Khans.

Relay stations were used to give food, shelter and spare horses for Mongol army messengers. Genghis Khan gave special attention to Yam because Mongol armies traveled very fast, so their messengers had to be even faster, covering 200–300 km per day. The system was used to speed up the process of information and intelligence.

The system was preserved in Russian Tsardom after the disintegration of the Golden Horde.

The Yam operated with a chain of relay stations at certain distances to each other, usually around 14 miles to 40 miles apart. Messengers for example someone would go to the next relay station and give the information to the second messenger and rest and let the second messenger go to the third relay station to hand the document to the third messenger. This way information or documents were constantly on the move without each messenger getting tired. In each relay station there would be spare horses, food, and shelter.

As one of the most fundamental tools for managing the Mongol Empire, the operation of the Yam system was regulated by the written law Yassa. Both messengers and station operators enjoyed extended privileges. Even for everybody else, the requirements of the Yam took precedence before their other duties and interests, and they had to support it whenever it became necessary. This kind of support was made possible by the strict discipline within the empire, which also led to a high level of security, often described as Pax Mongolica.

At first the system was also available to merchants free of cost. The abuse of this possibility led Möngke Khan to require that commercial users pay for the services.

...
Wikipedia