Who is Cai Ze 蔡泽？

Cai Ze 蔡泽(birth and death years unknown), a native of Gangcheng in Yan State during the Warring States Period (present-day Huai'an or Wanquan, Hebei Province), was a skilled debater and wise strategist who deeply understood the philosophy that *"when the moon is full, it begins to wane."* After persuading Fan Sui (Lord Yinghou) to retire after achieving success by pointing out the danger of *"killing the hound once the rabbit is caught,"* he was recommended by Fan Sui to become Prime Minister of Qin under King Zhaoxiang. He served four rulers: King Zhaoxiang, King Xiaowen, King Zhuangxiang, and Qin Shi Huang, preserving himself through the turbulent era. After King Huiwen, he devised strategies for King Zhaoxiang to alienate King Anxi of Wei from Lord Xinling and to annex the Eastern Zhou Dynasty, being granted the title "Lord Gangcheng." He resided in Qin for over a decade and, during Qin Shi Huang's reign, was dispatched on a mission to Yan as Lord Gangcheng.  

Cai Ze's Philosophy
Philosophically inclined toward Daoism, he emphasized the idea of *"retiring after achieving merit."* He stated: *"The four seasons follow their order—what has completed its task must depart,"* and *"As the saying goes: 'When the sun reaches its zenith, it begins to decline; when the moon is full, it starts to wane.' Prosperity inevitably leads to decline, a constant law of heaven and earth. Advancing or retreating, expanding or contracting with the times—this is the constant path of sages"* (*Records of the Grand Historian: Biography of Cai Ze*). Citing the deaths of four meritorious figures—Wen Zhong (Minister of Yue), Wu Qi (Prime Minister of Chu), Shang Yang (Reformer of Qin), and Bai Qi (General of Qin)—who were killed or forced to commit suicide, he argued that retreat was necessary to avoid disaster: *"These four men achieved merit but did not retire, leading to their downfall. This is what happens when one can only 'advance' but not 'retreat,' only 'stretch' but not 'bend'"* (ibid.). He asserted that all things involve both *qu* (bending) and *xin* (stretching), *wang* (going) and *fan* (returning), and that official positions should likewise allow for both promotion and demotion. Those who *"cannot descend after ascending, cannot bend after stretching, cannot return after going"* (ibid.) will invite disaster. He opposed *"endless greed for profit"* and advocated Daoist principles of minimal desire and knowing when to stop: *"Jade birds, swans, rhinoceroses, and elephants are not naturally close to death, yet they perish because they are lured by bait. The wisdom of Su Qin and Zhi Bo was sufficient to avoid humiliation and death, yet they died because they were consumed by unending greed. Thus, sages establish rites to restrain desires, levy taxes moderately, use resources sparingly, and act in harmony with the Dao, ensuring their legacy endures"* (ibid.). He believed that only by embracing minimal desire and knowing when to stop could one remain invincible. His biography appears in *Records of the Grand Historian* (Chapter 79).  

Early Life
In his early years, Cai Ze traveled throughout the states, studying under masters and seeking official positions from various rulers, but he was never significantly employed. Once, he visited the physiognomist Tang Ju and asked: *"I hear you once told Li Dui, 'You will hold power within 100 days'—is this true?"* Tang Ju replied affirmatively. Cai Ze then asked, *"What do you make of me?"* Tang Ju examined him and smiled: *"You have a upturned nose, hunched shoulders, a protruding forehead, a flat nose, and bowed legs. I hear sages do not rely on appearance—could this refer to you?"* Realizing Tang Ju was jesting, Cai Ze said, *"Wealth and honor are already within my grasp; what I do not know is my lifespan. I hope to hear your opinion."* Tang Ju replied, *"You have 43 years left."* Cai Ze laughed, thanked him, and departed. He then told his charioteer: *"Eating fine rice and meat, riding in a carriage, holding a golden seal, wearing a purple sash, and being respected by the ruler—43 years of such glory will suffice."* He left Yan for Zhao but was expelled, then traveled to Han and Wei, where robbers stole his cooking utensils.  

Debating Fan Sui
Upon learning that Fan Sui (Lord Yinghou), who had recommended Zheng Anping and Wang Ji, felt ashamed after their crimes in Qin, Cai Ze traveled west to Qin. Before meeting King Zhaoxiang, he deliberately provoked Fan Sui by spreading rumors: *"Cai Ze, a scholar from Yan, is a brilliant debater. Once he meets the King of Qin, he will surely displace you."* Fan Sui scoffed: *"I understand the principles of the Five Emperors, Three Kings, and the teachings of the Hundred Schools. I have refuted many eloquent speakers—how can this man challenge me?"* He summoned Cai Ze, who entered with a casual salute. Annoyed by Cai Ze's arrogance, Fan Sui demanded: *"Did you really claim you would replace me as Prime Minister?"* Cai Ze replied, *"Yes."*  

Fan Sui challenged him to explain, and Cai Ze began: *"Why are you so slow to understand? The four seasons replace each other) after completing their roles. A scholar desires a healthy body, sharp senses, and a wise mind, does he not?"* Fan Sui agreed. Cai Ze continued: *"Upholding benevolence, justice, and virtue to fulfill one's aspirations, winning the world's respect—this is the goal of wise debaters, is it not?"* Fan Sui assented. Cai Ze then asked: *"To enjoy wealth, honor, and longevity, to leave a lasting legacy praised for generations—this is the ultimate good, is it not?"* Fan Sui again agreed.  

Cai Ze pressed: *"Do you envy the fates of Shang Yang (Qin), Wu Qi (Chu), and Wen Zhong (Yue), who died tragically?"* Sensing Cai Ze's intent, Fan Sui deflected: *"Why not? Shang Yang served Duke Xiao with unwavering loyalty, enforcing laws to secure peace; Wu Qi strengthened Chu without fear of danger; Wen Zhong saved Yue from destruction. They are paragons of virtue and loyalty. A gentleman dies for honor, so why envy them?"

Cai Ze retorted: *"A wise ruler with a virtuous minister is a blessing. But Bi Gan (Zhou) and Wu Zixu (Wu) were loyal yet failed to save their states because their rulers were unwise. Shang Yang, Wu Qi, and Wen Zhong were right, but their rulers were wrong. Would you envy their unrecognized deaths? If loyalty requires death, then Wei Zi (Zhou) could not be called benevolent, Confucius a sage, or Guan Zhong great. Should one not seek to survive while achieving merit? The best outcome is to preserve both life and reputation; the next is to leave a legacy through death; the worst is to survive with a tarnished name."* Fan Sui conceded this was well argued.  

Seizing the moment, Cai Ze asked: *"Compared to Hong Yao (Zhou) and the Duke of Zhou, how do Shang Yang, Wu Qi, and Wen Zhong rank as ministers?"* Fan Sui admitted they were inferior. Cai Ze continued: *"Is your ruler (King Zhaoxiang) more benevolent or loyal than Duke Xiao of Qin, King Dao of Chu, or King Goujian of Yue?"* Fan Sui avoided answering. Cai Ze pressed: *"Your achievements and favor exceed those three ministers, yet you hold greater power and wealth. If you do not retire, you risk a worse fate than them. The sun sets after zenith, the moon wanes after fullness—this is the natural law. The sage adapts to timing. Look at Duke Huan of Qi, Fu Chai of Wu, and Xia Yu—all fell due to arrogance and greed. Shang Yang, Bai Qi, Wu Qi, and Wen Zhong died because they could not retreat. Fan Li (Tao Zhu Gong) understood this and retired to live as a wealthy hermit. As a gambler knows when to bet big or small, you have now reached the peak of your power in Qin. If you do not retire, you will meet the same end as those four. 'Look in water to see your face; look at others to see fortune and misfortune.' The *Book of History* says, 'Merit and fame cannot endure forever.' Why suffer their fate? Retire now, yield your position to a worthy successor, and enjoy a life of honor like Boyi, with eternal nobility and longevity like Wang Qiao and Chisongzi. Is this not better than disaster? Hesitate, and you will share their fate."*  

Fan Sui conceded: *"Desire without satisfaction leads to loss; possession without restraint leads to ruin. Thank you for your guidance—I will follow your advice."* He invited Cai Ze to be his guest of honor.  

Serving as Prime Minister of Qin
A few days later, Lord Yinghou (Fan Sui) attended court and said to King Zhaoxiang of Qin: "There is a new guest from Shandong named Cai Ze. He is an eloquent speaker who thoroughly understands the affairs of the Three Kings, the achievements of the Five Hegemons, and the changes in worldly customs. The grand affairs of Qin can entirely be entrusted to him. I have met many people, but none can match him, not even myself. I Presumptuous report this to you." King Zhaoxiang summoned Cai Ze, and after conversing with him, greatly admired him, appointing him as a guest minister. Taking this opportunity, Lord Yinghou pleaded illness and requested to return his prime ministerial seal. Although the king urged him to continue his duties, Lord Yinghou insisted he was seriously ill. Fan Sui was thus relieved of his position as Prime Minister. Impressed by Cai Ze’s strategies during their first meeting, King Zhaoxiang appointed Cai Ze as Prime Minister of Qin, and he later annexed the Eastern Zhou Dynasty to the east.
After serving as Prime Minister for several months, Cai Ze faced malicious slander. Fearing for his life, he feigned illness and returned his seal, receiving the title "Lord Gangcheng." He resided in Qin for over a decade, serving Kings Zhaoxiang, Xiaowen, and Zhuangxiang. Finally, under Qin Shi Huang, he was dispatched as an envoy to Yan. Three years later, Crown Prince Dan of Yan became a hostage in Qin.