Ubasi Khong Tayiji was a 17th century Mongolia

Mongolia

Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...

n prince. He was the first Altan Khan of Khalkha

Altan Khan of Khalkha

The Altan Khans ruled north-western Mongolia from about 1609 to 1691 at the latest. Altan Khan of Khalkha also known as Altan Khan of Khotgoid ruled over khotgoids in northwestern Mongolia and belonged to the Left Wing of the Khalkha Mongols...

 who ruled Khotgoids in northwestern Khalkha See Altan Khan of the Khotgoid.
About 1609 he occupied the former Oirat heartland around Kobdo and Lake Ubsa Nor

Uvs Nuur

Uvs Lake is a highly saline lake in an endorheic basin - Uvs Nuur Basin in Mongolia with a small part in Russia. It is the largest lake in Mongolia by surface area, covering 3,350 km² at 759 m above sea level....

. He drove the Oirats west into Dzungaria

Dzungaria

Dzungaria, also called Zungaria, is a geographical region in northwest China corresponding to the northern half of Xinjiang. It covers approximately , lying mostly within Xinjiang, and extending into western Mongolia and eastern Kazakhstan...

 in 1620 and 1623. Ubasi was killed by the Oirats in 1623 and was succeeded by his son Badma Erdeni Khong Tayiji.