Sun Chongjin was a native of the northern territory called Zhenwu (振武; around modern
Hohhot,
Inner Mongolia). He began following
Li Keyong when the latter attacked
Shuozhou (in modern
Shanxi) and became an adopted son some time later with the new name
Li Cunjin. After the suppression of the rebel
Huang Chao, Li Cunjin rose to a commissioner of Army of Righteous Sons (義兒軍使). After the death of Li Keyong, Li Cunjin served Li Keyong's successor Li Cunxu when their
Jin state fought the
Later Liang. In 910, Li Cunjin helped his lord win the battle at
Baixiang County (in modern
Hebei), and was promoted to inspector-in-chief of forces at large (行營馬步軍都虞候) to govern Cizhou (慈州; modern
Ji County, Shanxi) and Qinzhou (沁州; modern
Qinyuan County, Shanxi). After 915, he became a chief officer (都部署) of the newly conquered Tianxiong Command (天雄軍). There he instilled strict measures on the surrendered Later Liang troops: anyone violating the regulations would be openly beheaded or dismembered, and this approach effectively prevented any possible unrest. He was promoted to
military governor of Zhenwu Command (振武軍; headquartered in modern Hohhot) after participating in the battles along the
Yellow River. In 921,
Zhang Wenli usurped the power in
Zhao, eliciting a military response from Li Cunxu. The attacks were unsuccessful as many Jin generals died in battles, including
Li Sizhao. Li Cunxu then asked Li Cunjin to replace Li Sizhao as the commissioner of bandit suppression (招討使). As the soil was poor at the crossing where he quartered his men, he was not able to construct ramparts, so
palisades were made instead. When the palisade went under attack by the troops of Zhang Wenli's son
Zhang Chujin, Li Cunjin rose atop a bridge to direct his troops and died in the battles. He was conferred a grand marshal (太尉) posthumously. His son Li Hanshao (李漢韶), later renamed Sun Hanshao (孫漢韶), also became a military general. ==References==