Zhang Yi, promoting the policy of horizontal alliance for the state of Qin, sought to persuade the King of Han, saying: "The terrain of Han is perilous, and the people dwell mostly among the mountains. The grains they sow are none other than wheat and beans; what the people eat is for the most part bean rice and bean-leaf broth. Should a year pass without harvest, the people cannot even fill themselves with dregs and chaff. The land of Han stretches no more than nine hundred li in breadth, and holds not two years' store of grain. Estimating Your Majesty's forces, in their entirety they number no more than three hundred thousand, and of these are counted the laborers and purveyors. Setting aside those who guard the borders, patrol the marches, and hold the forts, those who can take the field number but two hundred thousand. The state of Qin, by contrast, fields a million armored soldiers, a thousand war chariots, and ten thousand steeds. Its warriors, fierce as tigers, who charge barefoot and bare-headed, with glaring eyes and brandished halberds, are too many to be counted. The war-horses of Qin are excellent, its soldiers numerous; the steeds gallop and leap, with fore and hind hooves spanning three xun, in numbers beyond reckoning. The soldiers of the states east of the mountains don armor and helmets to join battle, but the men of Qin cast off their armor and fight bare-chested, bearing in the left hand a severed head and clasping beneath the right arm a captive. When the armies of Qin are matched against those of the six states east of the mountains, it is as the warrior Meng Ben matched against a coward; when their overwhelming strength is brought to bear, it is as the mighty Wu Huo set against an infant. To deploy warriors such as Meng Ben and Wu Huo against a weak state that refuses to submit is no different from pressing a weight of a thousand jun upon a bird's egg—there can be no hope of survival. The feudal lords, without measuring the weakness of their own forces or the scantiness of their provisions, yet heed the glib persuasions of the advocates of the vertical alliance. They band together and embellish one another's words, all saying: 'Follow my counsel and you shall dominate the realm.' They give no thought to the long-term welfare of their states, but heed only the rhetoric of the moment. None is more culpable than they in misleading their sovereigns. If Your Majesty does not serve Qin, Qin will send its forces to occupy Yiyang, sever Your Majesty's Shangdang region, and press eastward to seize Chenggao and Xingyang—then the Hongtai Palace and the Sanglin Park will no longer be yours. Should Chenggao be blocked and Shangdang severed, Your Majesty's state will be split asunder. To serve Qin first is to be safe; to refuse Qin is to court danger. To invite calamity while seeking fortune, to harbor shallow schemes yet incur deep enmity, to turn against Qin and follow Chu—even should one wish not to perish, it cannot be. Thus, for Your Majesty's consideration, none is better than to serve Qin. What Qin most desires is to weaken Chu, and none is more suited to weakening Chu than Han. This is not because Han is stronger than Chu, but because Han's geographic position is advantageous. If Your Majesty turns westward to serve Qin and attack Chu, the King of Qin will surely rejoice. To attack Chu and possess its lands, to deflect calamity and delight Qin—there is no better stratagem than this." Thereupon the King of Qin dispatched me to present this letter to Your Majesty's censor, awaiting Your Majesty's decision. The King of Han replied: "I am grateful for your instruction. I am willing to unite all of Han, from the highest to the lowest, in serving Qin."
💡 商战启示录
Zhang Yi's policy of "horizontal alliances" in persuading Han was fundamentally about dismantling the vertical alliance through demonstrations of relative strength and geopolitical interests, compelling weaker states to submit to the stronger power. In modern commercial warfare, this strategy manifests as follows: in competitions marked by unequal resources, the weaker party should assess the situation prudently and choose strategic cooperation over blind confrontation. For instance, when small and medium-sized enterprises face industry giants, engaging head-on in price wars or technological contests often proves enormously costly and rarely yields victory. A superior approach—akin to Han's "serving Qin"—is to proactively ally with the titan, becoming an indispensable link in its ecosystem. Many startups, for example, choose to accept investment from Tencent or Alibaba, leveraging their platforms and traffic to fuel their own growth. Furthermore, Zhang Yi emphasized "attacking Chu while privately seizing its territory"—that is, securing tangible benefits through cooperation. This reminds enterprises that partnership must not merely seek safety but must clearly define the exchange of interests. The merger of Didi and Kuaidi serves as an apt illustration: after joining forces, they ceased their cash-burning subsidy war, shared the market, and achieved a win-win outcome. Additionally, in commercial warfare, "vertical alliances" often take the form of industry coalitions or price cartels, yet these are frequently fragile due to internal conflicts of interest. Enterprises should assess the stability of such pacts, guard against being swayed by "sweet words and flattering rhetoric," and instead make rational decisions grounded in their own strength and core interests—ready, when necessary, to pivot decisively, turning adversaries into allies and crises into opportunities.