The boundaries of the easter part of the Jochi Ulus were largely defined by military operations conducted by Jochi himself.  Thus, it is quite proper to consider him not only the namesake of the Ulus, but the true founder, which has not always been appreciated. The origins of the Jochid Ulus began in 1207 when Chinggis Khan sent his eldest son to secure the submission of the Hoy-in Irgen.

His successful campaign and later participation in the quelling of a Hoy-in Irgen revolt secured the Irtysh River as the eastern boundary of the Ulus.  After the battle of the Irtysh River, Jochi marched deep into the Dasht-i Qipchaq. While it did not immediately bring these territories under his control, his participation in the hunting of Merkit refugees did play an important role in delineating Jochid territory years later, also well as determining what territory would not be in it. The campaign against the Khwarazmian Empire defined the southern border, roughly following Jochi’s march towards Urgench.

Finally, the western border was also established at this time along the Yaik or Ural River. While Jochi has been often portrayed as petulantly withdrawing to the Dasht-i Qipchaq after Urgench and amusing himself by hunting rather than waging war, in reality, Jochi remained quite active in the war effort, occupying the eastern Dasht-i Qipchap. Furthermore, he procured needed supplies for Chinggis Khan’s armies through the hunt.  This paper will examine this process of defining the limits of the early Jochid ulus as well as how Jochi’s military campaigns were instrumental in determining them rather than imperial decree.