The state of Jin was originally named Tang, a fief granted by King Cheng of the early Western Zhou Dynasty to his younger brother Shu Yu. Shu Yu's descendants renamed it Jin and moved its capital successively to Quwo, Jiang, and Xintian. In the late Western Zhou, Marquis Wen of Jin helped King Ping of Zhou move the capital eastward, making a great contribution to the establishment of the Eastern Zhou. After Duke Wu of Jin ascended the throne, he captured the Rong Di chieftain Guizhu alive and later named his own son Guizhu. When Duke Wu died, Guizhu succeeded him, becoming Duke Xian of Jin.
When Duke Xian of Jin ascended the throne, the State of Jin was merely a "remote marquisate with small territory and powerful states nearby." Its later rise to become one of the Five Hegemons of the Spring and Autumn Period was entirely due to the solid foundation laid by Duke Xian. He pursued a policy of honoring the Zhou king, enhancing Jin's prestige among the feudal lords; he dealt severe blows to the stubborn and conservative old nobility, weakening the power of the old slave-owning aristocracy; and he vigorously cultivated the enterprising non-royal ministerial families, creating conditions for the growth of the emerging feudal forces.
Duke Xian of Jin actively expanded his power and territory, deciding to seize the strategic Xiaohan region to the south. To the south of Jin lay the states of Yu (north of present-day Pinglu, Shanxi) and Guo (within present-day Shan County, Henan), which were neighboring states with strong diplomatic ties; whenever Duke Xian of Jin attacked one, the other would send troops to aid it, and their combined forces posed a formidable challenge to Jin.
Duke Xian of Jin sought advice from his ministers, and the senior official Xun Xi said that the state of Yu was located on the northern border of the state of Guo, making it the necessary route for Jin to attack Wei. He thus proposed first borrowing a path through Yu to attack Guo, isolating Yu, and then waiting for an opportunity to destroy Yu. He said: "We must first drive a wedge between the two states. The ruler of Yu is shortsighted, greedy for small gains, and fond of fine horses and beautiful jade. We can use the excuse that Guo frequently invades Jin's borders, cater to his tastes, and he will surely agree to lend us the path."
Duke Xian of Jin was somewhat reluctant to part with these treasures, but Xun Xi understood his thoughts and advised, "My lord, rest assured—these treasures are merely being temporarily stored with Duke Yu of Yu; once we have conquered the state of Yu, won't they be yours again?" Duke Xian of Jin found this reasoning sound and thus adopted Xun Xi's strategy.
Duke Yu received treasures gifted by the state of Jin and could not bear to put them down, and Xun Xi was so eloquent that he persuaded Duke Yu to immediately agree to lend a passage, and although the ministers of Yu repeatedly advised against it, Duke Yu, having gained benefits from Jin, insisted on allowing Jin to borrow the route to attack the state of Guo.
That summer, the State of Jin captured Xiayang (in present-day Pinglu, Shanxi), a key stronghold of the State of Guo, thereby controlling the vital passage between Guo and Yu. Subsequently, Jin deliberately provoked incidents along the border between Jin and Guo, eventually finding a pretext to attack Guo. Jin then repeated its old tactic of requesting passage through Yu, promising to share the spoils of war with Yu.
When Gong Zhiqi, a senior official of the Yu State, heard about this, he firmly opposed allowing the Jin State passage through Yu. He said to Duke Yu that Yu and Guo were close neighbors, as interdependent as lips and teeth—if Guo was destroyed, then "when the lips are gone, the teeth will feel cold," meaning Yu would surely fall next. Therefore, he urged Duke Yu never to agree to let Jin pass through their territory.
But Duke Yu believed that Jin and Yu were from the same ancestral lineage and would not deceive him, and moreover, Jin had specially sent fine horses and beautiful jade, which fully demonstrated their sincerity in seeking friendship with Yu; now they only wanted to borrow a road to pass through, which would do no harm to Yu. Gong Zhiqi could only sigh repeatedly in helplessness, and foreseeing that Yu would surely be destroyed before long, he took his family and left the state of Yu.
In 656 BCE, the Jin army breached the capital of the Guo state, Shangyang, and destroyed Guo. Then, Jin temporarily stationed its troops in Guo to rest and reorganize. The Jin general Li Ke feigned illness, delaying the army's return to Jin, and the Duke of Yu did not suspect anything. Later, Duke Xian of Jin invited the Duke of Yu to go hunting outside the city. While the Duke of Yu was away hunting, the troops stationed in Guo launched an attack on the capital of Yu. Duke Xian of Jin captured the Duke of Yu, and thus the state of Yu was easily eliminated by Jin.