Zhou–Chu War

[22] The war took place in the middle Yangtze region, which was dominated by marshes, swamps, and mountains,[3] but still very fertile[23] and extremely rich in ores like gold,[24] copper and tin.

[25] As result of its natural wealth, the area not only spawned several highly developed Neolithic cultures,[23] but also garnered the attention of the peoples living in the Central Plain.

[32] Even though Shang rule over eastern Hubei had mostly collapsed by the 14th century BC, the dynasty continued to be active in the middle Yangtze area.

Oracle bone inscriptions report both the continued existence of a few Shang-loyal enclaves in Hubei, such as E, Zeng, and Chü, as well as many military campaigns against southern peoples.

Archaeological findings show no cultural unity in the region after the Erligang period, making the existence of a larger, centralized power unlikely.

Instead, the end of Shang rule allowed several small but highly developed native centers to emerge, which possibly led to "a flowering of civilization at this stage".

[37] Largely freed from foreign dominance, these polities became economically, technologically, and politically highly advanced,[38][8] while also growing in military strength.

Perhaps, speculates Ralph D. Sawyer, Yu Xiong had recognized that the Shang dynasty was crumbling or he simply wanted to ensure good relations with all powerful neighbors.

Just as the Shang people before them, the new dynasty began to heavily rely on imported ores from the southern mines to sustain their own growing large-scale bronze production.

[53] These findings correspond with contemporary bronze inscriptions, which show that the dynasty was initially focused on expanding to the east and north, while leaving the southern polities mostly alone.

After his predecessors had mostly secured the Zhou empire's eastern, northern and western borders, King Zhao turned his attention to the south and began a major military and colonial venture directed at the middle Yangtze area.

[59] Based upon later historiographies, Charles Higham believes that this had been the case for Chu: It had rapidly expanded after the Shang-Zhou transition, growing in power and influence and uniting large swaths of the Han River and the middle Yangtze valleys under its control.

[60] Sawyer notes, however, that even if Chu and other natives appeared as threat to King Zhao, the Zhou acted as primary aggressors through several invasions into the Yangtze area.

[4][3] From there, the combined troops of the royal armies and the vassal states conquered the area north of the Yangtze, and then crossed the Han River, where King Zhao encountered a rhinoceros, which was interpreted as an auspicious sign.

[50][38] These campaigns were well prepared and planned through the construction of forward bases, the use of local allies, such as the states of Fang, Deng and Eh, and diplomatic ventures.

As he employed half of Zhou's royal forces, organized into the "Six Armies of the West",[11] Li Feng and Ralph D. Sawyer believe that this massive assault indicated Zhao's desire to permanently bring the middle Yangzi region under his control by completely destroying Chu.

[3] Driven back, the Zhou wanted to retreat across the Han River, but according to the Lüshi chunqiu the bridge they used collapsed, casting both the king and the Duke of Cai into the waves.

[64] However, despite his "humiliating end", King Zhao was still sometimes commemorated for his southern campaigns, as he had at least established political dominance over the region to the north of the Yangtze and east of the Han River.

[61] The Zhou were also able to rebuild the lost Six Armies of the West during the reign of Zhao's successor, King Mu,[65] and successfully defended the kingdom against ensuing foreign invasions.

As Chu had firmly established its autonomy and control over the middle Yangtze region, there was no longer any need to openly defy the Zhou monarchs.

Following his father's death, King Mu led a punitive campaign against the confederation to force it back into full submission, but was unsuccessful.

[52] Possibly to check the confederation's expansion, the Zhou dynasty moved its vassal state of E into the Nanyang Basin, north of Chu.

Prominent archeological sites of 1500-1040 BC. Panlongcheng and Wucheng are to the south.
In the tradition of his predecessors, King Zhao of Zhou desired to expand the Zhou kingdom through conquest.
At the time of King Zhao 's invasion, marshes such as these in Yangxin were common along both the Han River as well as the Yangtze .
After its victory over Zhou and the conquest of E , Chu grew into one of the most powerful states of the Spring and Autumn and Warring States periods .