Jisi Incident

The Jisi Incident (己巳之變) was a military conflict between the Later Jin and Ming dynasty, named because it happened in 1629, a jisi year according to the Chinese sexagenary cycle. In the winter of 1629 Hong Taiji bypassed Ming's northeastern defenses by breaching the Great Wall of China west of the Shanhai Pass and reached the outskirts of Beijing before being repelled by reinforcements from Shanhai Pass. The Later Jin secured large amounts of war material by looting the region around Beijing. This was the first time the Jurchens had broken through the Great Wall into China proper since they rose up against Ming China.

Course of battle
In the winter of 1629 the Jin army broke through the Great Wall at Longjin Pass and Da'an Pass, west of Shanhai Pass. The Jin first secured Jizhou by encircling it and then advanced towards Zunhua, which fell easily with the help of defectors. The Ming official Liu Zhilun attempted to thwart the Jin invaders with two units of gunners, but his men mutinied and they died under a volley of arrows. Zhao Shuaijiao also died at Zunhua.

Ming commander Man Gui rushed to intercept the Jin army with 5,000 troops, but they were repulsed and driven toward Beijing's Desheng Gate. Beijing's garrisons tried to support Man Gui with cannon fire, but ended up hitting his troops. Man Gui was forced to retreat into Beijing after losing 40 percent of his troops. Another Ming commander Hou Shilu attempted to intervene, but his forces were routed. At that point the Chongzhen Emperor started pleading the high officials in the capital to use their own personal funds and horses to supply the army.

As the Jin army was about to assault the northern wall of Beijing, Yuan Chonghuan arrived from the northeast with reinforcements and drove back the invaders. After that he was assigned the defense of the Guangqu Gate.

Man Gui's army attempted to fortify the outskirts of Beijing with palisades, but the Jin army attacked, crushing his forces, and killing Man Gui. Zu Dashou attempted similar operations, but was also defeated by Jin cavalry and forced to flee east. Another contingent of Ming forces was defeated at the Marco Polo Bridge. More reinforcements were called in from the west, which contributed to the general mayhem as they looted their way to Beijing.

Yongping fell to the Jin in early 1630 and the invaders captured some 22,000 taels as well as large amounts of food supplies. The Jin army attempted to advance further but was repulsed by Yuan Chonghuan.

Hong Taiji attempted to negotiate with the Chongzhen Emperor, but his envoys elicited no response. The Jin army retreated to Shenyang in the spring of 1630, but commanders and garrisons were left behind to occupy the cities they had captured.

The Ming managed to retake these cities by mid-spring of 1630.

Aftermath
While the Jin had not managed to capture Beijing, they acquired significant amounts of war booty in the form of taels, grain, supplies, weapons, and captives.

Hong Taiji released accusations through captured eunuchs implicating Yuan Chonghuan of colluding with him. Believing these claims, Chongzhen ordered the arrest and imprisonment of Yuan. Yuan was accused of having fired cannons at Man Gui's troops, colluding with the Jin, and executing Mao Wenlong on false charges. He was executed on 22 September 1630.