At one point, he was guilty of a crime, and he fled to Xuanwu Circuit (宣武, headquartered in modern Kaifeng, Henan).
[1] (While the accounts do not give a date for his defection, the fact that the History of the Five Dynasties referred to Xuanwu as "Bian Liang" (汴梁) by its prefectural and regional designations, suggests that this occurred in the very late Tang dynasty, when Hedong and Xuanwu were respectively ruled by powerful rival warlords Li Keyong and Zhu Quanzhong.)
After Zhu Quanzhong seized the throne and established Later Liang as its founding emperor, Kang was gradually promoted in the soldier ranks.
[2] In 923, Zhu Zhen commissioned his general Duan Ning to prepare to launch a major attack on Later Liang's archrival Later Tang—i.e., the successor state of what was the power bloc centered around Hedong, by this point ruled by Li Keyong's son Li Cunxu, who had just recently declared himself emperor.
[1] Li Cunxu took off his own silk robe and jade belt and awarded them to Kang, making him a commander in his own army against Later Liang, as well as the prefect of Bo Prefecture (博州, in modern Liaocheng).
He further revealed to Li Cunxu that Duan had an ambitious four-prong plan to attack Later Tang, to be launched in winter 923, to try to reverse years of Later Liang losses at the hands of Later Tang's predecessor state Jin:[3] Kang pointed out the weakness of the plan—that it divided up the Later Liang troops, making, in particular, Wang's and Zhang's army vulnerable.
They then confronted Wang and Zhang at Zhongdu (中都, in modern Jining, Shandong), defeating and capturing them.
Li Cunxu initially hesitated at heading toward Daliang directly, with most of his generals advocating by this point that he first capture Later Liang's coastal circuits.
This caught Zhu by surprise, as Duan's four-prong attack plan left Daliang defenseless.
[3] In 924, Li Cunxu made him the military governor of Baoyi Circuit (保義, headquartered in modern Sanmenxia, Henan).
He chose to take only his cavalry soldiers, fording on their horses, across the river, at the great loss of life from drowning, believing that he needed to quickly advance toward the Former Shu capital Chengdu in order to give the Former Shu emperor Wang Zongyan no chance to rest and think.
Further angered (believing that his military accomplishments entitled him to Dongchuan), Li Shaochen went to see Guo, ostensibly to recommend Ren Huan instead.
When he reached Jian Prefecture (劍州, in modern Guangyuan, Sichuan), he declared himself the military governor of Xichuan Circuit (西川, headquartered at Chengdu), claiming to be displacing Meng Zhixiang, whom Li Cunxu had commissioned and who was already at Chengdu by that point.
He had Li Shaochen brought to the feast table in his jail wagon (i.e., a mobile jail cell mounted on the wagon), stating to Li Shaochen, "You, Lord, already held the staff and flag of a military governor, and also had great accomplishment in conquering Shu.
Li Shaochen responded, "Chancellor Guo had the highest accomplishments, including conquering the two Chuans [(i.e., Dongchuan and Xichuan)] without dirtying his sword.