During Shi Jingtang's reign After Shi Jingtang overthrew then-Later Tang emperor
Li Congke (Li Siouan's adoptive son) in 936 and established his state of
Later Jin, he made Li Shouzhen his imperial protocol officer (客省使,
Keshengshi). Li Shouzhen served as Ma's army monitor during the campaign, Li Shouzhen was given the dual offices of commander of the imperial cavalry guards and military governor of Yicheng Circuit (義成, headquartered in modern
Anyang,
Henan). His imperial guard office was soon changed to be discipline officer of the imperial guards. When the Liao general Yelü Mada () tried to attack Shi Chonggui himself directly during the campaign, Li Shouzhen intercepted and defeated him. After the end of that campaign, Shi, while retaining him as discipline officer, also made him the military governor of Taining Circuit (泰寧, headquartered in modern
Jining,
Shandong). Around the new year 945, Yang Guangyuan's son Yang Chengxun () put his father under house arrest and surrendered to Li. With Yang Chengxun's having surrendered on his own, Shi, while believing that Yang Guangyuan deserved death, did not want to execute him publicly, and therefore had Li secretly send executioners to batter Yang to death, while publicly claiming that Yang had died of an illness. Around this time, his military governorship was moved from Guide to Tainting (天平, headquartered in modern
Tai'an,
Shandong). In 946, there was a report from Ding Prefecture (定州, in modern
Baoding,
Hebei) that another Liao attack was impending. Shi Chonggui sent Li to the frontier to command an army against the potential invasion, with Huangfu Yu () serving as his deputy. However, with the report apparently being a false alarm, Li, after minor border skirmishes, was returned to his position at Chan. (It was said that at this time, Li Yantao had become particularly powerful as Shi's close associate, such that he had Li Shouzhen's every move under control. Li Shouzhen, in response, outwardly showed respect and deference to him, while inwardly resented his influence on the emperor.) Meanwhile, with Li Shouzhen's troops having to often go through Guangjin (廣晉, in modern
Handan,
Hebei), Du, who was then the military governor of Tianxiong Circuit (天雄, headquartered at Guangjin), frequently got the chance to welcome him and often gifted him with gold, silk, armors, and elite soldiers, causing them to become good friends. Whenever Shi held feasts for Li Shouzhen and praised him for battlefield accomplishments, Li Shouzhen would thus praise Du for his contributions and suggest that, in the future, if there were to be a major attack against Liao, he and Du could work together, and Shi agreed. In 946, there were rumors that the major Liao general
Zhao Yanshou—who had previously been a major Later Tang general before being captured by the Khitan in the campaign that led to Later Tang's destruction—was planning on defecting to Later Jin. This rumor was believed by Li Song and Feng, who then served as Shi's chief of staff. They had Du write a letter to Zhao, encouraging him to do so, with the officer Zhao Xingshi (), who had previously served under Zhao Yanshou, delivering the letter. Zhao Yanshou wrote back (to try to lead Later Jin forces into a trap), stating, "I have long been in a foreign land, and I want to return to China. Please launch a major army to support me, so that I can pull myself out and return with it." Subsequently, under Emperor Taizong's orders, Liao's prefect of Ying Prefecture (瀛州, in modern Cangzhou), Liu Yanzuo (), also offered to defect to Later Jin. Shi thus put Du and Li Shouzhen in command of an army to attack north, with the stated objectives being to first recapture the prefectures Shi Jingtang previously ceded to Liao (the
Sixteen Prefectures), and then to destroy Liao. (Zhao Ying, however, had reservations, pointing out that Du, despite his honored position, was still often dissatisfied with his station, and therefore suggested to Li Song and Feng that Li Shouzhen be put in command by himself; Zhao Ying's suggestions were not listened to, however.) When Du and Li Shouzhen advanced, though, they were met by a large army that Emperor Taizong personally commanded. The Liao army eventually surrounded the Later Jin army at Zhongdu Bridge (中度橋, in modern Baoding). After Emperor Taizong made the promise to Du to make
him emperor if he surrendered, Du and Li Shouzhen surrendered their army. (As part of accepting Du's surrender, Emperor Taizong had Zhao mockingly put an imperial robe on Du.) Emperor Taizong then prepared to advance south. He commissioned Li Shouzhen '
Situ (司徒, one of the
Three Excellencies) as well as continuing to the military governor of Tianping, and had Li Shouzhen and Du accompany him south. With virtually the entire Later Jin army having been given to Du and Li Shouzhen for this northern campaign, Kaifeng was left essentially defenseless, and Shi felt compelled to surrender, ending Later Jin. Emperor Taizong subsequently entered Daliang. == During submission to Liao ==