Spring and Autumn Period - Interstate Relations

Interstate Relations

Shortly after the royal family's move to Chengzhou, a hierarchical alliance system arose where the Zhou king would give the title of hegemon to the leader of the state with the most powerful military; the hegemon was obligated to protect both the weaker Zhou states and the Zhou royalty from the intruding non-Zhou peoples: the Northern Di, the Southern Man, the Eastern Yi, and the Western Rong. This political framework retained the fēngjiàn power structure, though interstate and intrastate conflict often led to disregard for feudal customs, respect for the Ji family, and solidarity with other Zhou peoples. The king's prestige legitimized the military leaders of the states, and helped mobilize collective defense of Zhou territory against "barbarians."

Over the next two centuries, the four most powerful states—Qin, Jin, Qi and Chu—struggled for power. These multi-city states often used the pretext of aid and protection to intervene and gain suzerainty over the smaller states. During this rapid expansion, interstate relations alternated between low-level warfare and complex diplomacy

Ancient sources such as the Zuo Zhuan and the eponymous Chunqiu record the various diplomatic activities, such as court visits paid by one ruler to another (朝, cháo), meetings of officials or nobles of different states (會, huì), missions of friendly inquiries sent by the ruler of one state to another (聘, pìn), emissaries sent from one state to another (使, shǐ), and hunting parties attended by representatives of different states (狩, shou).

Because of Chu's non-Zhou origin, the state was considered semi-barbarian and its rulers – beginning with King Wu in 704 BC – proclaimed themselves kings in their own right. Chu intrusion into Zhou territory was checked several times by the other states, particularly in the major battles of Chengpu (632 BC), Bi (595 BC) and Yanling (575 BC), which restored the states of Chen and Cai.

The first hegemon was Duke Huan of Qi (r. 685-643 BC). With the help of his minister, Guan Zhong, Duke Huan reformed Qi to centralize its power structure. The state consisted of 15 "townships" with the duke and two senior ministers each in charge of five; military functions were also united with civil ones. These and related reforms provided the state, already powerful from control of trade crossroads, with a greater ability to mobilize resources than the more loosely organized states. By 667 BC, Qi had clearly shown its economic and military predominance, and Duke Huan assembled the leaders of Lu, Song, Chen, and Zheng, who elected him as their leader. Soon after, King Hui of Zhou conferred the title of bà (marshall), giving Duke Huan royal authority in military ventures. Using this authority, Duke Huan intervened in a power struggle in Lu; protected Yan from encroaching Western Rong nomads (664 BC); drove off Northern Di nomads after they'd invaded Wey (660 BC) and Xing (659 BC), providing the people with provisions and protective garrison units; and led an alliance of eight states to conquer Cai and thereby block the northward expansion of Chu (656 BC).

At his death in 643 BC, five of Duke Huan's sons contended for the throne, causing enough state discord that the next Duke of Qi did not inherit the bà title. For nearly ten years, no ruler held the title. However, when Duke Wen of Jin (r. 636–628 BC) came to power, he capitalized on the reforms of his father, Duke Xian (r. 676–651 BC), who had centralized the state, killed off relatives who might threaten his authority, conquered sixteen smaller states, and even absorbed some Rong and Di peoples to make Jin much more powerful than it had been previously. When he assisted King Xiang in a succession struggle in 635 BC, Xiang awarded Jin with strategically valuable territory near Chengzhou.

Duke Wen of Jin then used his growing power to coordinate a military response with Qi, Qin, and Song against Chu, which had begun encroaching northward after the death of Duke Huán of Qi. With a decisive Chu loss at the Battle of Chengpu (632 BC), Duke Wen's loyalty to the Zhou king was rewarded at an interstate conference when King Xīang awarded him the title of bà.