Battle of Loulin

Battle of Loulin
Part of the Xu-Chu wars and the Qi-Chu wars
Date Winter 645 BC Location Loulin (present-day Fengyang County, Anhui) 32°52′00″N 117°34′00″E / 32.866667°N 117.566667°E / 32.866667; 117.566667 Result Chu victory
Belligerents
Xu Qi Lu Song Chen Wey Zheng Cao Xǔ	Chu
Commanders and leaders
Gongsu Ao(Lu commander) Several unknown commanders	Unknown Chu commander
Location within China

The Battle of Loulin was fought in Winter 645 BC between the states of Chu and Xu, the latter being supported by a coalition of northern states led by Qi. Xu, originally the most powerful state of the Huai River valley, had been weakened by internal unrest and several wars since the beginning of the Spring and Autumn period. As its influence over eastern Hubei, southern Henan and central Anhui waned, Chu began to expand into these regions. Threatened by these developments, Xu joined an alliance of several northern states against Chu. In spring 645 BC, when Chu invaded Xu's southern heartland, the northern states sent a relief expedition in order to aid Xu and stop Chu's eastern conquests. The coalition forces eventually met Chu's army at Loulin and were defeated, marking the beginning of Xu's final decline and accelerating the end of Qi's hegemony over China.

The state of Xu, centered in northern Anhui, had controlled most of the middle and lower Huai River during the Western Zhou and early Spring and Autumn period. Beginning in the late 8th century BC, however, Xu's power began to wane, and several of its vassals and territories seceded. At the same time, the state of Chu in eastern Hubei rose in prominence.

After it had conquered most of the Nanyang Basin in 678 BC, Chu began to advance further east into the Upper Huai River valley and north into the Yangtze plain. In just twenty years, it overrun many neighboring states and forced others into vassalage. Troubled by Chu's growing power, the hegemon of China, Duke Huan of Qi, began to organize a major alliance to invade Chu and end its expansion. Coinciding with the formation of the anti-Chu alliance, Xu occupied the state of Shu in modern-day Lujiang County in 656 BC. Li Lian, a Yuan dynasty scholar, considered it likely that Shu had been an ally of Chu and Xu had taken it in coordination with Qi. According to this view, the destruction of Shu was part of the preparation for the planned invasion of Chu by the northern alliance. The Kangxi Dictionary editors found this theory reasonable. In this case, the conquest of Shu marked the beginning of hostilities between Chu and Xu, the latter acting in accordance with Qi. In 655 BC, Qi launched its invasion of Chu together with Song, Chen, Wey, Zheng, Xǔ, and Cao. The offensive quickly stalled, however, and the alliance was unable to weaken Chu. A non-aggression pact was concluded, whose only consequence was that Chu decided to expand further into the Huai River valley instead of attacking the northern states again. Consequently, it began to expand more aggressively into Xu's sphere of influence and conquered several small Huai states.