Gepo Campaign

The Gepo Campaign, or the Ge Slope Campaign, was launched by the Han-Zhao general, Shi Le against the Western Jin dynasty from February to July 312. The initial objective of the campaign was to conquer the Jianghuai region, which was controlled by the Prince of Langya, Sima Rui. However, due to severe famine and plague within his army, Shi Le was forced to turn back north in search for a stable base. The campaign concluded in Jin victory but also saw the end of Shi Le's time as a roving commander as he established a base at the city of Xiangguo.

In mid-311, the Han-Zhao general, Shi Le annihilated the imperial Jin army at the Battle of Ningping. Subsequently, Han forces led by Wang Mi and Liu Yao captured Luoyang and Emperor Huai of Jin in the Disaster of Yongjia. Though the Han had finally won a monumental victory over the Jin, internal strife continued to plague them, in particular the growing ambition of Shi Le. Not long after the fall of Luoyang, Shi Le assassinated Wang Mi at a banquet and absorbed his forces. The Han emperor, Liu Cong was furious, but in reality, his court in Pingyang only had nominal control over affairs outside the Shanxi region. He was forced to tolerate Shi Le's actions, in turn affirming Shi Le's authority over Han forces to the east of Shanxi.

Meanwhile, to the south of the Yangzi river, the Jin Prince of Langya, Sima Rui was consolidating his rule over Yang province with the help of the cousins, Wang Dao and Wang Dun, along with the native southern gentry clans. He had avoided sending troops to help fight the Han in the north, but his dominion became a safe haven for northern emigres fleeing from the war. Following the disaster, he was appointed leader of the Jin alliance and granted imperial power to appoint and dismiss major officials by a provisional government led by the Minister of Works, Xun Fan. The prince capitalized on his new powers by ousting the Jin inspectors of Jiang and Yu provinces and installing officials loyal to his regime.

Shi Le had ambitions to control the regions around the Yangzi and Han rivers; he had previously campaigned against the rebel, Wang Ru and reached as far south as Xiangyang in 310, but was forced to turn back north at the advice of his Commandant of Army Advisors, Zhang Bin, as hunger and plague killed more than half of his soldiers. In November 311, Shi Le led his forces to pillage Yu province, reaching the banks of the Yangzi before turning back to camp at Gepo (葛陂; northwest of present-day Xincai County, Henan). There, he rejected an offer to defect from the Jin Inspector of Bing province, Liu Kun, even despite returning his mother, Lady Wang (王氏), and adopted brother, Shi Hu. Shi Le initially attacked Xingyang near Luoyang, but after he was badly defeated in an ambush by the local Jin administrator, Li Ju, he turned his sights once more to the south.

In February or March 312, Shi Le began fortifying his camp, farming and building ships in preparation to attack Sima Rui's base at Jianye. In response, Sima Rui gathered all his soldiers at Shouchun and placed them under the command of his General Who Displays Might, Ji Zhan. However, Shi Le's campaign quickly turned for the worse as great storms appeared and heavy raining persisted into the following month. More than half of his men died of starvation or disease, and he was also receiving several proclamations from Sima Rui's sides stating their intention to attack. Thus, Shi Le gathered his generals for an emergency council.

His Chief Clerk of the Right, Diao Ying (刁膺), suggested they feign submission to Sima Rui; once the Jin army withdraws, they would have ample time to plan their next step. His general, Kui An, urged that they move to higher ground to avoid the waters. Kong Chang, along with more than 30 other generals, volunteered to launch a daring night attack on Shouchun. Shi Le rejected all their proposals. He then consulted Zhang Bin, who advised him:

"General, you have captured the imperial capital, imprisoned the Son of Heaven, murdered his princes and violated his women. The hair on your head will not be enough to count the crimes you have committed, so how can you consider serving as their minister? We should not have come here after you killed Wang Mi last year, and now Heaven is heavily pouring rain for hundreds of lis around telling you not to remain here. Ye boasts the fortifications of the Three Terraces, bordering Pingyang to the west and surrounded by mountains and rivers. March north and capture it, then all of Hebei will be for us to take. After the Hebei is secured, no general in the realm will be able to stand against you.
The Jin is defending Shouchun because they are afraid you would attack them. They will be content with saving themselves when they hear that we are leaving. Why would they pursue us and put themselves at risk? General, you should send the baggages and supplies to the north first, then lead the main army towards Shouchun. Once our supplies are far away enough, the main army can slowly withdraw. Why worry about having no place to advance or retreat?"

Shi Le was pleased with Zhang Bin's plans, so much so that he had Diao Ying demoted for suggesting he surrender and replaced him with Zhang Bin. In accordance to the plan, he sent out Shi Hu with 20,000 cavalry towards Shouchun. Shi Hu encountered and attacked Jin forces building boats, hoping to capture them, but was defeated by Ji Zhan. As Shi Hu retreated, Ji Zhan pursued them for several miles until he met Shi Le's main army. Shi Le had his troops in a defensive formation and prepared for an attack, but Ji Zhan decided to withdraw back into Shouchun instead.