The Tongjian on the Warring States Period

The Warring States period (475 to 221 BCE) is where the Zizhi Tongjian begins, and for good reason. It was the era when seven kingdoms fought for supremacy over two and a half centuries, developing the political strategies, military doctrines, and diplomatic maneuvers that would define Chinese statecraft for the next two thousand years. Sima Guang used this opening section to establish his method: chronologically trace how decisions at court produced outcomes on the battlefield, and how battlefield outcomes reshaped the political map.

Seven Kingdoms, One Prize

By the fifth century BCE, the Zhou dynasty had fragmented into dozens of states, and through centuries of warfare and annexation, seven major powers emerged: Qi, Chu, Yan, Han, Zhao, Wei, and Qin. Each had its own geographic advantages, political culture, and strategic doctrine. Qi was wealthy and culturally sophisticated. Chu was vast, southern, and militarily aggressive. Qin was western, initially considered semi-barbaric by the other states, but possessed the most effective military and administrative system.

The Tongjian traces how these seven states competed through alternating periods of alliance and betrayal. The period is defined by the practice of he zong (合纵, vertical alliances) and lian heng (连横, horizontal alliances), where traveling diplomats (纵横家, zongheng jia) persuaded kings to join coalitions against whichever state was currently strongest. The alliances shifted constantly, and the Tongjian records each shift with its consequences.

Qin’s Rise: The Legalist Formula

The Tongjian pays close attention to why Qin won. The answer Sima Guang presents is institutional, not charismatic. Qin’s advantage was not a series of brilliant kings or generals, though it had both. It was the reforms of Shang Yang (商鞅), implemented in the fourth century BCE, that transformed Qin from a backward frontier state into the most efficient war machine of the ancient world.

Shang Yang’s reforms were uncompromising. He abolished the hereditary aristocracy, replacing it with a merit-based military rank system where promotion depended on battlefield performance measured in enemy heads. He redistributed land to farmers, breaking the power of old feudal families. He standardized weights, measures, and law across the state. He encouraged agriculture and punished laziness. The result was a state where every resource was directed toward military power, and where individual advancement depended entirely on service to the state.

The Battle of Changping: The Turning Point

The Tongjian treats the Battle of Changping (260 BCE) as the decisive turning point of the Warring States period. Zhao, the strongest remaining challenger to Qin, fielded an army of roughly 450,000 men. Qin matched it. The campaign lasted for months, with both sides struggling to supply their enormous forces.

The decisive moment came when Zhao replaced its experienced general Lian Po with Zhao Kuo, a young officer known for theoretical brilliance but lacking battlefield experience. This replacement was the result of Qin espionage: Qin agents spread rumors in Zhao that Lian Po was cowardly and that Zhao Kuo was the only general who could defeat Qin. The Zhao king believed the rumors and made the switch.

The result was catastrophe. Zhao Kuo abandoned Lian Po’s defensive strategy and launched an offensive. Qin’s general Bai Qi encircled the Zhao army, cut its supply lines, and after forty-six days of starvation, accepted the surrender of approximately 400,000 Zhao soldiers. Then he ordered them all buried alive. The Tongjian records this without editorializing the horror, letting the act speak for itself.

Changping demonstrates a principle Sima Guang returns to throughout the Tongjian: the most consequential decisions are often personnel decisions. The Zhao king’s choice to replace a proven general with an untested one, based on enemy propaganda, destroyed his state’s military capacity in a single afternoon. The battle was lost before it was fought, in the audience chamber where the replacement was decided.

Diplomacy as Warfare: The Role of the Zongheng Jia

The Warring States period produced a class of professional diplomats known as the zongheng jia (纵横家), or “school of vertical and horizontal alliances.” These were traveling persuaders who moved from court to court, arguing for alliances that would benefit whichever state was currently paying them. The most famous were Su Qin, who advocated a vertical alliance of the six eastern states against Qin, and Zhang Yi, who argued for horizontal alliances with Qin against individual eastern states.

The Tongjian records their speeches and their effects with careful attention. Sima Guang was interested in them not as moral examples but as case studies in how rhetoric shapes policy. A skilled persuader could convince a king to commit his army to a war that served the persuader’s interests rather than the king’s. The results were often disastrous for the state that followed the advice, but the persuader moved on to the next court and the next fee.

The Fall of the Other Six States

After Changping, Qin’s victory was a matter of timing and method. Han fell first in 230 BCE, the smallest and weakest of the seven. Zhao fell in 228 BCE, still weakened by Changping. Wei fell in 225 BCE, when Qin general Wang Ben flooded its capital by diverting a river. Chu, the largest state, required the largest army and fell in 223 BCE after a sustained campaign. Yan fell in 222 BCE. Qi, the last to hold out, surrendered without significant resistance in 221 BCE when Qin’s armies appeared at its borders.

The Tongjian presents the conquest not as a single brilliant campaign but as the accumulated result of decades of institutional advantage. Qin had better logistics, more disciplined troops, a more efficient administrative system, and a clearer strategic vision. The other states had moments of brilliance but could not sustain institutional coherence across reigns. Qin’s Legalist system, for all its brutality, produced consistent results because it did not depend on the personal qualities of individual rulers.

For more on the Warring States in context, see the Zizhi Tongjian pillar page and the parent article covering 1,300 years of statecraft. The aftermath of Qin’s conquest and the dynasty’s rapid collapse is covered in the next chapter on the Qin collapse. For Sima Qian’s account of the same period, see the Shiji pillar page.

Why the Other States Could Not Match Qin

The Tongjian implicitly asks why none of the other six states managed to implement reforms as effective as Qin’s. The answer it provides is political. Qin’s relatively isolated western position meant its aristocracy was weaker and its ruler had more freedom to impose structural changes. In the eastern states, entrenched noble families resisted reform because it threatened their hereditary privileges.

Several states attempted reforms. King Wuling of Zhao introduced cavalry reforms, adopting nomadic-style mounted archery and trousers instead of traditional robes. Wei was an early reformer under Li Kui. Chu attempted reforms under Wu Qi. But in each case, the reforms were partial, opposed by the aristocracy, and reversed after the reforming ruler or minister died. Qin’s advantage was not that it had better ideas. It was that it had the political conditions to implement them fully and sustain them across generations.

Sima Guang’s lesson here is about institutional persistence. A reform that lasts one reign is a experiment. A reform that lasts three reigns is a system. Qin’s Legalist reforms survived Shang Yang’s own death (he was executed by the next ruler, but his laws remained) because they had become embedded in the administrative structure. The reforms in other states died with their sponsors because they never became institutional.

The Tongjian‘s treatment of the Warring States establishes the pattern it will follow for the next 1,300 years: identify the structural conditions, trace the decisions made within those conditions, and show how the consequences of those decisions reshaped the conditions for the next round. The Warring States is the test case. Every dynasty that follows is judged by whether it learned the lessons the Warring States taught or repeated the mistakes that destroyed its predecessors.

Frequently Asked Questions

Why does the Tongjian start with the Warring States rather than earlier periods?

Sima Guang chose 403 BCE as his starting point because it was the year the Zhou king formally recognized the three partitions of Jin into Han, Zhao, and Wei. This act of royal recognition legitimized the breakdown of the feudal order, and Sima Guang saw it as the beginning of a new era in which force rather than ritual determined political reality. Earlier periods were covered by the Spring and Autumn Annals and the Zuo Zhuan, which he did not need to duplicate.

How does the Tongjian’s account of the Warring States differ from the Shiji?

The Shiji organizes its Warring States material biographically, with chapters on individual rulers, ministers, and diplomats. The Tongjian reorganizes the same material chronologically, so you can see how events in different states interacted in the same year. This makes it easier to understand alliance dynamics but harder to follow an individual’s complete career.

Was the Battle of Changping really 450,000 soldiers?

The figures come from ancient sources and are debated by modern historians. The absolute numbers may be inflated, as ancient Chinese sources often exaggerated military figures for dramatic effect. However, there is broad consensus that Changping was an exceptionally large engagement and that the mass killing of surrendered Zhao soldiers occurred. The strategic consequences, whatever the exact numbers, were decisive.

Did Sima Guang approve of Qin’s methods?

No. Sima Guang was a Confucian who saw Legalism as morally corrosive. He presents Qin’s rise as effective but brutal, and he treats the dynasty’s rapid collapse after unification as evidence that a state built purely on coercion cannot last. His commentary on the Warring States consistently favors moral governance over pure power politics, even when he acknowledges that moral governance lost.