Yam (route)

The yam or jam (Russian: ям), also called the örtöö (Mongolian: өртөө, lit. 'checkpoint'), was a Mongol postal system or supply point route messenger system. It was extensively used and expanded by Ögedei Khan and also used by subsequent great khans and khans.

Relay stations provided food, shelter and spare horses for Mongol army messengers. Ögedei Khan gave special attention to the yam because Mongol armies travelled quickly; their messengers had to be even faster, and they covered 200–300 kilometres (120–190 mi) per day. The system was used to speed up the process of information and intelligence.

The system was preserved in Russia after the disintegration of the Golden Horde in the 15th century.