Huang Taiji had publicly stated that he…

Huang Taiji had publicly stated that he would never be able to beat Yuan in a fair game, thus, making the Chongzhen Emperor kill him had been the only method to get rid of him.

When the message of Yuan's death reaches Huang Taiji, he changes the name of the manchu state from Jin to Qing and proclaims himself Emperor Qing Taizong.

Some historical information states that Huang Taiji feared Yuan's last word stating his soul will always guard Liaodong Peninsula: As the name Chonghuan means Undying Flames, containing the element "Fire", Huang Taiji had chosen the word Qing, meaning cleanse, which contains the element "Water", to overcome it; however, even if this is the case, the main reason is probably because the "Ming" of the Ming Dynasty contains the element "Fire" itself.