Four years after being enfeoffed, the Marquis of Rang commanded Qin forces against Wei. Wei surrendered 400 square li of territory east of the Yellow River. He seized Wei's Henei region and took over sixty cities large and small. In King Zhao's nineteenth year, Qin proclaimed itself "Western Emperor" and Qi "Eastern Emperor." After little more than a month, Lu Li came, and both Qi and Qin abandoned their imperial titles and reverted to being kings. Wei Ran served again as Qin's chancellor for six years before being dismissed. After two years, he was restored as chancellor. Four years later, he sent Bai Qi to capture Ying, the Chu capital, and Qin established the Nan Commandery. Bai Qi was then enfeoffed as Lord Wuan. Bai Qi had been recommended and promoted by the Marquis of Rang, and they were on close terms. By this point, the Marquis of Rang's wealth exceeded that of the royal house.
In King Zhao's thirty-second year, the Marquis of Rang served as Chancellor of State and led troops to attack Wei. He routed Mang Mao, entered Beizhai, and then besieged Daliang. The Wei official Xu Jia addressed the Marquis: "I have heard Wei's senior officials tell the King of Wei: 'In the past, King Hui of Liang attacked Zhao, won at Sanliang, and took Handan, but Zhao refused to cede territory and Handan was restored. Qi attacked Wey, took the old capital, and killed Ziliang, but Wey refused to cede territory and the land reverted. The reason Wey and Zhao kept their states intact with strong armies and their territory was not annexed by other lords was that they could endure hardship and valued their land. Song and Zhongshan were repeatedly invaded and ceded territory, and their states followed them into ruin. I consider Wey and Zhao worthy models, and Song and Zhongshan cautionary tales. Qin is a rapacious and violent state with no sense of kinship. It has devoured Wei like a silkworm, consumed the whole of Jin, defeated Baozi in battle, and carved off eight counties — and before that territory was even fully absorbed, its armies came out again. Is there any end to Qin's appetite? Now it has routed Mang Mao and entered Beizhai — this is not merely an attack on our capital but an attempt to coerce the king into ceding more territory. The king must not agree. If the king abandons Chu and Zhao to make terms with Qin, Chu and Zhao will turn hostile and compete to curry Qin's favor, and Qin will accept them. Qin would then use Chu and Zhao's forces to attack Liang again, and the state could not escape destruction. I urge the king to absolutely refuse to negotiate. If the king must negotiate, concede only a little and demand hostages — otherwise, you will certainly be deceived.' This is what I have heard from Wei, and I ask you, my lord, to consider it in your deliberations. The Zhou Documents say: 'Heaven's mandate does not rest in one place forever' — this means that luck cannot be counted on repeatedly. Your victory over Baozi and the seizure of eight counties was not due to superior military skill or brilliant strategy — it owed much to heaven's favor. Now, routing Mang Mao and entering Beizhai to attack Daliang is treating heaven's favor as a sure thing. A wise man does not do this. I hear that Wei has marshaled all soldiers above fighting age from its hundred counties to defend Daliang — no fewer than 300,000, I believe. With 300,000 men defending Liang's walls of seven ren height, I maintain that even Tang and Wu come back to life could not easily take it. To lightly turn your back on the armies of Chu and Zhao, assault walls seven ren high, fight 300,000 men, and be determined to take the city — I believe that from the time heaven and earth were first divided until now, this has never been done. If you attack and fail to take it, Qin's army will be exhausted and your fief of Tao will certainly be lost, and all your previous achievements will be thrown away. Now Wei is wavering and can be won over with modest concessions. I urge you, my lord, before the armies of Chu and Zhao reach Liang, to quickly accept a small cession and secure Wei's allegiance. Wei is wavering and would see a small concession as advantageous; they will certainly agree, and then you, my lord, will get what you want. Chu and Zhao will be angry that Wei acted first, and they will compete to serve Qin — the vertical alliance will collapse, and you can take your pick afterward. Moreover, must you acquire territory only through force? If you carve up Jin's territory, Qin need not attack and Wei will readily offer up Jiang and Anyi. And if you open two roads to Tao, taking nearly all of former Song, Wey will offer up Shanfu. Qin's army can be kept intact while you control the situation — what could you seek and not obtain, what could you attempt and not achieve? I urge you to deliberate carefully and not pursue danger." The Marquis of Rang said: "Good." He lifted the siege of Liang.
