The Ming Dynasty gave Borjigin princes (descended from Genghis Khan's brothers) command of the Taining guard, one of the Three Guards which were established in 1389. During invasions of Esen Tayisi in 1446–48, most of the guards fled. However, the Fuyu Guard, another of the Three Guards, remained along the Nen River and Onon River. Ruled by descendants of Khasar, they became direct ancestors of the Khorchins.
Adai Khan of the Khorchin challenged the power of the Four Oirats and the Ming court in the succession struggle of Northern Yuan Dynasty. However, he was killed by them in Ejene in 1438 and his tribe was forced to flee southward. The Khorchin appeared again in Mongolian chronicles with the rise of Unebolad wang in the late 15th century. The Khorchins allied with Dayan Khan and defeated the Uriyangkhai at the battle of Dalan Terqin in 1510.