袁崇焕
The Later Jin had lost at the Battle of Ningyuan the previous year and their khan Nurhaci died from his wounds afterwards. Peace negotiations with the Ming after the battle delayed an aggressive Ming response to the Jurchen loss, and the Ming general Yuan Chonghuan was busy fortifying the border garrisons and training new musketeers. The new Khan Hong Taiji was eager for a quick victory to consolidate his position as khan. By invading Joseon he also hoped to extract much-needed resources for his army and subjects, who had suffered in the war against Ming.