The Choras Sum in Tost village comprises a group of people who escaped the Jungar-Qing war and eventually settled in Khar Us. After the Torghuts migrated eastwards to Xinjiang from the Volga region, the Choras community was incorporated into the Torghuts and organised as one of the Torghut Sums. Over the course of 300 years, the Choras gradually assimilated into the Torghut groups, and few of them are aware of their historical roots, simply identifying as Torghuts. However, the Choras Oboo worship ritual reflects their distinctiveness from the Torghut groups.