Its elaboration and its discipline were the work of the khan, a relentless reflection of his brilliant clairvoyance. It was based on the ancestral decimal system:squads of ten men forming a hundred, the hundreds a thousand, the thousands a tumen, or ten thousand horsemen. And in every company of ten men there was a chief, and of the ten chiefs of a centurion one was chosen to command the centurion, and of the ten chiefs of ten centurions one commanded a thousand, usually a lord , and among these ten lords, one ruled a tumen. All advanced united, dependent on each other, and on this point the yasaq was formal:no soldier could leave his unit of ten, a hundred or a thousand to which he was assigned, even to join another. Anyone who broke this law was put to death, and the nine companions of his ten as well, including the chief. If ten men from the same unit fled and the centurion to whom they depended did not catch up with them, the whole centurion was shot.
The khan enforced this unstoppable organization as soon as auxiliary troops threatened to outnumber the Mongol ranks. These troops were composed of subjugated enemy tribes, mercenaries, slaves, freed or not, volunteers or conscripted. And among them, we counted Tatar, Merkit, Khitan, Kèrèit, Naiman, Oïrat, Khirgiz, Ongut, Tangout, Kin and Djurtchèt, and even Sartes, the latter being very often used as spies in the outskirts of Khwazrem. Each formation often depended on the authority of a Mongol. Thus, in a centurion, it was not uncommon to see ten Mongol lieutenants leading ninety convinced federates who, in this pyramidal structure, had no racial problem. All were treated the same, obeyed the same, and helped each other unto death. The kin slave, like the blood prince, was rewarded or punished in the same way. Certainly the commanders of the thousands were Mongol lords, those of the tumen, princes or faithful heroes of the khan, but their responsibilities did not allow them the slightest relaxation.