The Warring States Background

The early Warring States period (475-221 BCE) witnessed relatively limited conflicts between feudal states. The three Jin states (Han, Wei, Zhao), united by common interests, frequently launched joint campaigns against Qi and Chu. Major wars often erupted when stronger states intervened to protect weaker ones. By the mid-Warring States period, the emergence of vertical (合纵) and horizontal (连横) alliances dramatically expanded both the scale and frequency of warfare.

Initially, vertical alliances represented coalitions of weaker states resisting Qin’s aggression, exemplified by Gongsun Yan’s united campaign against Qin, primarily motivated by the three Jin states suffering under Qin pressure. As the rivalry between the two superpowers Qi and Qin intensified, both began manipulating these alliances as tools to overwhelm their opponent and facilitate further conquests. When one power felt threatened, it would exploit conflicts between its rival and other states to organize a vertical alliance. After subduing the opponent, the victor would ruthlessly expand while compelling weaker states to assist its conquests.

Qin’s Strategic Expansion

Under Duke Xiao’s reign (361-338 BCE), the Legalist reforms of Shang Yang gradually strengthened Qin, enabling the recovery of lost territories west of the Yellow River. Subsequently, King Huiwen employed strategists like Zhang Yi and generals including Sima Cuo to expand Qin’s borders in all directions – northeast to Wei’s Hexi and Shangjun, east to Shan controlling the Yellow River and Xiaohan Pass, southwest conquering Ba and Shu, and northwest capturing twenty-five cities from Yiqu.

Following the failure of Gongsun Yan’s vertical alliance and success of Zhang Yi’s horizontal strategy, Qin achieved a major victory over Chu at Danyang, seizing Hanzhong. King Wu altered Qin’s expansion strategy by dispatching Gan Mao to capture Han’s major county Yiyang, establishing a foothold in the Central Plains.

During King Zhaoxiang’s early reign (306-251 BCE), the successful vertical alliance organized by Qi’s chancellor Lord Mengchang saw Qi-Wei-Han forces breach the Hangu Pass, forcing Qin to return some captured lands and temporarily stalling its expansion. However, after Lord Mengchang’s exile from Qi and Bai Qi’s decisive victory over the Han-Wei coalition at Yique, Qin compelled Wei to surrender four hundred li east of the Yellow River and Han to yield two hundred li along the Wusui to Pingyang corridor.

The Tripartite Balance of Power

After King Wuling of Zhao (325-299 BCE) implemented “Hu clothing and cavalry archery” reforms and conquered Zhongshan and Hu territories, a tripartite balance emerged between Qin, Qi and Zhao. Qin chancellor Wei Ran devised a scheme for Qi and Qin to jointly declare themselves emperors and partition Zhao, but this failed due to Su Qin’s vertical alliance. After Su Qin’s five-state coalition against Qin collapsed, Qin organized its own successful five-state alliance against Qi, appointing Yue Yi as joint chancellor of Zhao-Yan and commander of the allied forces that eventually crushed Qi, leaving Qin as the dominant power.

Subsequently, Qin expanded southwest to capture Chu’s Qianzhong, south to seize the Chu capital Ying, while compelling Han and Wei to surrender Nanyang. Simultaneously, Qin completed the conquest of Yiqu in the northwest. Under Kings Huiwen and Zhaoxiang, Qin dramatically expanded its territory, establishing commanderies including Ba, Shu, Hanzhong, Shangjun, Hedong, Longxi, Nanjun, Qianzhong, Nanyang and Beidi.

The Path to Unification

By King Zhaoxiang’s reign, Qin had essentially begun the unification wars, seizing vast territories from eastern states while inflicting massive casualties. Major battles commanded by Bai Qi include:
– 293 BCE Yique: 240,000 Han-Wei troops decapitated
– 279 BCE Yan: Tens of thousands of Chu soldiers and civilians drowned
– 273 BCE Huayang: 150,000 Zhao-Wei troops killed
– 260 BCE Changping: 450,000 Zhao soldiers buried alive

These four major battles alone eliminated over a million soldiers from the three Jin states and Chu, critically weakening their military capacity and laying Qin’s foundation for ultimate victory. However, Qin’s brutal tactics, particularly the massacre of surrendered troops, provoked intense Zhao resistance, leading to Qin’s three-year siege of Handan ending in failure when Wei-Chu forces relieved Zhao and counterattacked to Hedong.

Despite temporary eastern victories, these states couldn’t diminish Qin’s power. After regrouping, Qin resumed unification campaigns, capturing two Han cities and compelling the Western Zhou ruler to surrender territory. With the symbolic Zhou king’s death, Qin’s unification wars gained legitimacy. By Kings Xiaowen and Zhuangxiang’s reigns, unification had become inevitable.

Cultural and Strategic Impacts

The period witnessed several significant developments:
1. Military Reforms: Zhao’s adoption of Hu cavalry tactics revolutionized warfare
2. Diplomatic Maneuvering: The complex vertical-horizontal alliance systems reflected sophisticated interstate relations
3. Economic Integration: Qin’s administrative reforms in conquered territories facilitated economic unification
4. Technological Advancements: Qin’s military technology, including advanced bronze weaponry, provided strategic advantages

Legacy of Qin’s Unification

Qin’s military successes established China’s first centralized empire, creating administrative models that endured for millennia. The standardization of writing, measurements, and laws across conquered territories forged cultural unity. Qin’s expansion also defined China’s geographical scope, incorporating diverse regions into a single political entity.

The Qin unification demonstrated how military strategy combined with administrative reforms could overcome fragmentation, setting precedents for subsequent Chinese dynasties. While the Qin dynasty proved short-lived, its institutional innovations and territorial framework became the foundation for China’s enduring civilization.