In order to attack and suppress the Northern Yuan dynasty, the Hongwu Emperor sent military commissions to gain control of the Jurchen tribes in Manchuria.

The Ming responded by dispatching expeditionary forces led by Military Commissioner Yang Hao along four routes to besiege Hetu Ala.

Relocating his court from Jianzhou to Liaodong provided Nurhaci access to more resources; it also brought him in close contact with the Khorchin Mongol domains on the plains of Mongolia.

Nurhaci's policy towards the Khorchins was to seek their friendship and cooperation against the Ming, securing his western border from a powerful potential enemy.

[5] The unbroken series of military successes by Nurhaci came to an end in January 1626 when he was defeated by Yuan Chonghuan while laying siege to Ningyuan.

He died a few months later and was succeeded by his eighth son, Hong Taiji, who emerged after a short political struggle amongst other potential contenders as the new khan.

One of the defining events of Hong Taiji's reign was the official adoption of the name "Manchu" (满洲) for the united Jurchen people in November 1635.

When he was said to be presented with the imperial seal of the Yuan dynasty by Ejei Khan, Hong Taiji renamed his state from "Jin" to "Great Qing" and elevated his position from Khan to Emperor, suggesting imperial ambitions beyond unifying the Manchu tribes, and marking the formal end of the Later Jin period.

Together these military reforms enabled Hong Taiji to resoundingly defeat Ming forces in a series of battles from 1640 to 1642 for the territories of Songshan and Jinzhou.

His five-year-old son, Fulin, was installed as the Shunzhi Emperor, with Hong Taiji's half brother Dorgon as regent and de facto leader of the Qing dynasty.