The Rise and Fall of Qi’s “Eastern Emperor”

In the chaotic era of the Warring States period (475–221 BCE), the state of Qi stood as one of the dominant powers, rivaled only by Qin in the west. For centuries, Qi’s prosperity rested on two pillars: its monopoly on sea salt production and its thriving maritime trade. Nestled along the Yellow Sea, Qi transformed seawater into precious salt—a commodity as vital to ancient life as grain. While other states relied on inland salt sources like Shanxi’s Xiezhou Salt Lake, Qi’s coastal position gave it unparalleled economic leverage.

The state’s second economic engine was its booming fish trade. Before tofu’s invention, protein-starved commoners relied on salted fish—Qi’s other major export—for sustenance. As the philosopher-merchant Lü Buwei noted, salt and fish were among the few goods that could reliably enrich a state, unlike luxury items like jade or bulk commodities like grain that were prone to price fluctuations.

The Mastermind Behind the Scenes: Su Qin’s Grand Scheme

Enter Su Qin, history’s first documented master spy. Disguised as a wandering strategist, this brilliant operative manipulated all seven major Warring States plus two minor kingdoms (Song and Zhongshan) like pieces on a chessboard. Though his immediate plans didn’t unfold as intended, his machinations ultimately determined the period’s final outcome—the unification under Qin.

Su Qin’s masterstroke came in 284 BCE when he orchestrated the “Five-State Alliance Against Qi.” This coalition—comprising Yan, Zhao, Wei, Han, and Qin—shattered Qi’s dominance after its ill-advised annexation of Song. The campaign reduced Qi’s territory by two-thirds, leaving only the cities of Ju and Jimo under its control.

The Salt Monopoly That Built an Empire

Qi’s economic dominance stemmed from its salt production techniques. While later generations would marvel at the inefficiency of boiling seawater (compared to solar evaporation), this method aligned perfectly with agricultural cycles. Winter—when fields lay fallow and dried crops provided abundant fuel—became salt-making season. The state strictly controlled production, creating what economists might call the world’s first commodity-based economy.

This wealth funded Qi’s military ambitions. Under rulers like King Min (齐湣王), Qi crushed Wei at Maling (341 BCE), humbled Chu, and even besieged Qin’s impregnable Hangu Pass. By 288 BCE, Qin’s King Zhaoxiang acknowledged Qi’s parity, offering mutual recognition as “Eastern and Western Emperors.”

The Spy’s Revenge: How Yan’s Humiliation Led to Qi’s Downfall

The seeds of Qi’s destruction were sown in 316 BCE during Yan’s bizarre “abdication crisis.” The aging King Kuai of Yan, desperate to emulate ancient sage-kings, fell for a honey-trap conspiracy by his prime minister Zi Zhi. In a parody of Yao and Shun’s legendary abdication, Kuai surrendered his throne—only for Zi Zhi to refuse returning it, plunging Yan into civil war.

Qi intervened under King Xuan, ostensibly to restore order but really to annex Yan. The campaign initially succeeded spectacularly—Qi’s armies took Yan’s capital in just fifty days. But occupation proved disastrous. Qi’s troops, behaving like conquerors rather than liberators, sparked rebellions. The philosopher Mencius famously criticized this heavy-handed approach, warning that “he who delights in killing will never rule All-under-Heaven.”

Su Qin’s Web of Deception

From 300 BCE onward, Su Qin—now Yan’s spymaster—wove an intricate trap:

1. Feigned Submission: He convinced Qi that Yan had accepted vassal status
2. The Song Gambit: Pushed Qi to annex wealthy Song, triggering neighbor states’ alarm
3. Five-State Alliance: Engineered a coalition that crushed Qi at the Battle of Jixi (284 BCE)

The aftermath was catastrophic. Qi’s King Min was flayed alive by Chu “allies,” its capital Linzi sacked, and its treasuries emptied. Yet remarkably, Qi survived—thanks to resistance in Ju and Jimo led by Tian Dan, whose legendary “fire oxen” tactics routed Yan’s occupation forces.

Legacy: The Unintended Path to Unification

Su Qin’s scheme had unintended consequences. While weakening Qi achieved Yan’s revenge, it removed the last counterbalance to Qin’s westward expansion. Within sixty years, Qin would conquer all warring states—including a subdued Qi that surrendered without fight in 221 BCE.

The salt trade that built Qi’s empire became its Achilles’ heel. After the war, Qin systematically seized all major salt production centers—Shanxi’s Xiezhou, Sichuan’s wells, and finally Qi’s coastal pans—giving it the economic base to fund unification.

As the Han historian Sima Qian noted, “Su Qin’s tongue moved mountains, but his plans buried kingdoms.” In destabilizing Qi, he inadvertently paved the road for China’s first imperial dynasty—a lesson in how espionage can reshape history’s trajectory.