Cao Can

Biography

Family Background and Early Life

Cao Can was from Pei County. His family background is unknown, but he had already acquired a local reputation before the fall of Qin. Under Qin rule he served as the prison official of Pei County, responsible for managing the jail, while Xiao He was a senior county clerk. Both were influential local officials. Liu Bang was then chief of Sishui Pavilion and ranked below Cao Can. Cao Can, Liu Bang, Xiao He, and Fan Kuai were all natives of Pei, but Xiao and Cao were officials in the county administration and were widely respected, whereas Liu Bang and Fan Kuai were of lower standing in the eyes of local elders.

Pei Uprising and the War against Qin

In the autumn of 209 BCE, the first year of the Second Emperor of Qin, Chen Sheng and others rose in rebellion at Qi County and established themselves at Chen under the name Zhangchu. People in many commanderies and counties killed local officials and responded to the revolt. The magistrate of Pei became alarmed and considered joining the rebellion. Xiao He and Cao Can advised him that, as a Qin official, he would have difficulty commanding the young men of Pei in rebellion and should summon men who had fled outside the county, giving him several hundred armed followers with which to compel obedience. The magistrate therefore sent Fan Kuai to summon Liu Bang, whose force had already grown to dozens or more than a hundred men.

When Fan Kuai returned with Liu Bang, the magistrate regretted his decision. Fearing that Liu Bang might seize power, he closed the city gates and planned to kill Xiao He and Cao Can. The two men fled over the wall and joined Liu Bang. Liu Bang wrote a message on cloth and shot it into the city, urging the elders of Pei to join the uprising. The elders then led the local youths in killing the magistrate, opened the gates, and welcomed Liu Bang. They wished to make him county magistrate, but Liu initially declined. Xiao He, Cao Can, and other civil officials valued the safety of their households and feared that if the revolt failed Qin would exterminate their clans, so they also declined leadership. After repeated urging, Liu Bang was finally established as Duke of Pei. Local youths and influential officials, including Xiao He, Cao Can, and Fan Kuai, then recruited roughly two to three thousand men.

After Liu Bang raised his standard as Duke of Pei, Cao Can followed him as zhongjuan. He joined attacks on Huling and Fangyu. The Qin commandery inspector Ping of Sishui Commandery led troops to besiege Feng, and Liu Bang's men returned to defend it. Two days later they attacked and defeated the Qin force. Cao Can participated in the fighting and helped rout the commandery inspector's troops. Liu Bang ordered Yong Chi to guard Feng while Cao Can moved east and captured Xue County. Liu Bang's main force defeated the Sishui administrator Zhuang west of the outer walls of Xue; Zhuang fled to Qi County and was captured and killed by Liu Bang's Left Sima.

Liu Bang's forces again attacked Huling. Xiao He and Xiahou Ying went to persuade Inspector Ping to surrender, after which the city yielded. Liu Bang returned toward Kangfu, but on reaching Fangyu found the Wei commander Zhou Shi attacking it. Before battle was joined Liu sent Cao Can to defend the city. Fangyu then shifted allegiance to Wei, and Cao Can led troops against it. Zhou Shi also persuaded Yong Chi at Feng to defect. Liu Bang tried but failed to retake Feng and, falling ill, had to return to Pei.

East of Dang County, Cao Can attacked the Qin general Sima Yi, identified in another account as Sima Xin, defeated him, and captured Dang, Hufu, and the postal station at Qi County. He then campaigned west of Xiayi as far as Yu County and engaged Zhang Han's forces. At Yuanqi and Kangfu, Cao Can led troops that were first over the walls. His rank was raised to Fifth Grandee.

Cao Can moved north to relieve Dong'e, attacked Zhang Han, broke through the enemy formation, and pursued as far as Puyang. He attacked Dingtao and captured Linji. Moving south to relieve Yongqiu, he defeated Li You's army, killed Li You, and captured one Qin military officer.

At this time Zhang Han defeated Xiang Liang and killed him, and Liu Bang and Xiang Yu withdrew eastward. King Huai of Chu appointed Liu Bang commandant of Dang Commandery and put him in charge of its forces. Cao Can was then granted the rank Zhibo and the title Lord of Jiancheng, and later promoted as Duke of Qi, the lord of Qi County, under Dang Commandery.

Cao Can subsequently followed Liu Bang against the Dong Commandery commandant and defeated his army south of Chengwu. He attacked Wang Li south of Chengyang, fought him again at Gangli, and inflicted another major defeat. Pursuing westward to Kaifeng, he attacked Zhao Ben and surrounded him inside the city. Farther west at Quyu he defeated the Qin general Yang Xiong and captured one Qin military officer and one censor, after which Cao Can's rank rose to Zhigui.

He then joined Liu Bang in attacking Yangwu, capturing Huanyuan Pass and Goushi County, blocking the Yellow River crossings, and turning back to defeat Zhao Ben north of Shixiang. He accompanied Liu Bang south to Chou County, where they fought the Nanyang administrator Lü Yi east of the outer wall of Yangcheng and broke his formation. Cao Can then joined the westward assaults on Wuguan and Yao Pass and helped seize both passes. The army fought Qin forces south of Lantian and again attacked north of Lantian at night, inflicting a major defeat before entering Xianyang and bringing the Qin dynasty to an end.

Chu-Han Contention

After Xiang Yu entered the Guanzhong region, he enfeoffed Liu Bang as King of Han. Liu Bang in turn made Cao Can Marquis of Jiancheng. Cao Can followed him to Hanzhong and was promoted to general.

When Liu Bang returned east to pacify the Three Qins, Cao Can joined attacks on Xiabian, Gudao, Yong, and Tai counties. South of Haozhi he defeated Zhang Ping's army, surrounded the city, and captured Rangxiang. He then defeated Three Qins forces east of Rangxiang and around Gaoli. When Zhang Ping broke out of Haozhi and fled, Cao Can attacked forces under Neishi Bao and defeated them. He moved east to capture Xianyang, which was renamed Xincheng.

Cao Can guarded Jingling for twenty days. Zhang Ping and other Three Qins commanders attacked him, but Cao Can went out to meet them and won a major victory. Liu Bang granted him Ningqin as a fief. Cao Can then, as general, participated in the siege of Zhang Han at Feiqiu and, holding the office of commandant, followed Liu Bang through Linjin Pass.

In Henei Commandery, the Han forces captured Xiuwu and crossed the Yellow River at Weijin. Moving east, Cao Can fought the armies of Long Ju and Xiang Ta at Dingtao and defeated them. The Han then took Dang, Xiao, and Pengcheng, but when they attacked Xiang Ji's army they suffered a major defeat and fled. As commandant, Cao Can besieged and captured Yongqiu. When Han generals Wang Wu at Waihuang and Cheng Chu at Yan County rebelled, Cao Can attacked and defeated both. He also suppressed a revolt by the Marquis of Zhutian at Yanshi, fought Yu Ying at Kunyang, pursued to Ye County, then returned to attack Wuqiang and finally reached Xingyang. From his appointment as general and commandant in Hanzhong until Xiang Yu's eventual defeat and his return to Xingyang, roughly two years had passed.

In 205 BCE, the second year of Han, Cao Can was appointed acting Left Grand Councilor and stationed in Guanzhong. More than a month later, King Bao of Wei rebelled. As acting Left Grand Councilor, Cao Can separately joined Han Xin's eastern campaign and at Dongzhang defeated the Wei general Sun Su. Pressing the advantage, they attacked Anyi and captured the Wei commander Wang Xiang. At Quyang they attacked the king of Wei and pursued him to Wuyuan, where Bao was captured alive. Cao Can then took Pingyang and captured Bao's mother, wife, and children. Fifty-two cities were brought under Han control, and Liu Bang granted Pingyang to Cao Can as a fief.

Cao Can later joined Han Xin in defeating the state of Dai and capturing its chief minister Xia Yue. Han Xin and Zhang Er used a deceptive deployment at Jingxing to draw out Zhao's main force, while Liu Bang advanced against Handan. As the Zhao position deteriorated, Chen Yu was caught between competing pressures. Han Xin and Zhang Er emerged through Jingxing, defeated and killed Chen Yu, while the Zhao commander known as General Qi fled west to Wu County and was killed by Cao Can, who was then operating in the Wei-Dai region. King Xie of Zhao fled to Xiangguo. Liu Bang, Zhang Er, and Han Xin attacked Xiangguo from north and south, captured it, killed King Xie, and pacified Zhao. Han forces later secured Julu and Changshan and received Yan's submission.

In 204 BCE, the third year of Han, Cao Can and others supported Han Xin's invasion of Qi and captured Licheng. The king of Qi fled to Gaomi and requested Xiang Yu's aid; Xiang Yu sent Long Ju to assist him. In the eleventh month of 203 BCE, the fourth year of Han, Han forces killed both King Tian Guang of Qi and Long Ju. Qi chancellor Tian Heng then proclaimed himself king, but Guan Ying defeated him at Ying County, and Tian Heng fled to Peng Yue. Cao Can remained in Qi to continue suppressing remaining resistance.

Founding of Han and Government in Qi

After Xiang Yu's defeat and death, Liu Bang became emperor. Apart from the feudal kings, the first ranking of eighteen marquises placed Xiao He first and Cao Can second, followed by Zhang Ao, Zhou Bo, Fan Kuai, Li Shang, Xi Juan, Xiahou Ying, Guan Ying, Fu Kuan, Jin Xi, Wang Ling, Chen Wu, Wang Xi, Xue Ou, Zhou Chang, Ding Fu, and Chong Da. Many ministers believed Cao Can should rank first because he had personally fought throughout the wars, received seventy wounds, and accumulated exceptional military merit. Liu Bang, however, regarded Xiao He's logistics and planning as even more important. Marquis E of Guannei argued that although Cao Can's battlefield achievements were great, the five years of Chu-Han war had consumed vast manpower and Xiao He continuously supplied troops from Guanzhong; at Xingyang, when the Han faced a food crisis, Xiao He's transport system kept the armies supplied. Although Xiao had not personally campaigned, he had protected Guanzhong and supported the emperor continuously, an achievement worthy of first place. The ministers accepted the argument, and Xiao He was ranked first, Cao Can second.

When Han Xin was transferred to become King of Chu, Cao Can returned the seal of chief minister. In 201 BCE, the sixth year of Han, Liu Bang enfeoffed his eldest son Liu Fei as King of Qi and appointed Cao Can to assist him as chief minister. Cao Can was also enfeoffed as Marquis of Pingyang with 10,630 households.

In 194 BCE, the first year of Emperor Hui, after the system of chief ministers in feudal kingdoms was abolished, Cao Can became Grand Councilor of Qi. Qi was a wealthy kingdom of seventy cities, and Cao Can sought an effective method of governance. Since Qi was a major center of Confucian learning, he consulted many scholars, but their advice differed so greatly that he did not know which view to follow. He then heard of Master Gai of Jiaoxi, a scholar of Huang-Lao statecraft, and invited him at great expense. Master Gai argued that after prolonged warfare the people should be left in peace and not disturbed by burdensome government so that society could stabilize. Cao Can established a separate residence for him, treated him as a political adviser, and governed Qi largely according to Huang-Lao principles. People throughout Qi came to praise Cao Can as a “worthy chancellor.”

Chief Minister of Han

In 193 BCE, the second year of Emperor Hui, Xiao He recommended Cao Can as his successor shortly before his death. Soon after Xiao died, Cao Can told his subordinates, “I will certainly succeed him as chief minister.” The court soon summoned him. Before leaving Qi, Cao Can instructed his successor that the execution grounds and prisons, referred to in the source as yushi, were crucial and that their existing arrangements should not be disrupted. When asked whether government amounted only to this, Cao Can replied that it did not, but that the inclusiveness of Huang-Lao governance depended on reliable implementation of criminal law: if judicial investigation and punishment were thrown into disorder, there would be nowhere for wrongdoers to be contained, which was why he mentioned it first.

As chief minister at the Han court, Cao Can spent much of his time drinking and eating, governed according to Huang-Lao principles, practiced non-interference, and continued Xiao He's policies without alteration. Emperor Hui found this strange and sent Cao Can's son Cao Zhu to remonstrate. Cao Can became furious, gave Cao Zhu two hundred lashes, and rebuked him for interfering in affairs of state. Emperor Hui therefore questioned Cao Can directly. Cao Can asked which was wiser, Emperor Hui or Emperor Gaozu. Hui replied that he could not compare himself with his father. Cao then asked who was more capable, himself or Xiao He. The emperor replied that Cao seemed inferior to Xiao. Cao Can answered that the emperor was correct: Gaozu and Xiao He had already pacified the empire and established clear and complete laws; the emperor needed only to rule calmly while ministers remained at their posts and observed the established regulations without violation. Contemporaries sang: “Xiao He made the laws, orderly and uniform; Cao Can succeeded him, guarding them without loss. Bearing their purity and quiet, the people found unity and peace.” The approach became known as “Cao followed Xiao's rules.”

According to the Book of Han, Cao Can and Xiao He had been close friends when both served in Pei County under Qin, but after the Han conquered the empire and Xiao became chief minister, relations between them deteriorated. Nevertheless, after Cao succeeded Xiao he changed none of Xiao's institutions. When subordinate officials committed minor faults, Cao Can often concealed them and gave the officials a chance to correct themselves. He served as chief minister of Han for three years before his death and received the posthumous title Marquis Yi.

His Conduct as Chancellor and the Famous Exchange

After succeeding Xiao He as chancellor of Han, Cao Shen "undertook nothing that altered the old arrangements and in all things followed Xiao He's rules," and his daily conduct drew a good deal of comment. The Records of the Grand Historian note that he "drank strong wine day and night," and that when officials and guests came hoping to speak to him, "when they arrived, Shen would give them strong wine; and when he judged that they wished to say something, he gave them more, so that they went away drunk and could never open the matter — this became his custom." The History of the Former Han puts it more plainly: his purpose was to leave those who came to plead or to ask favours without a chance to speak. The habit was copied by his subordinates, and the garden behind the chancellor's house adjoined the clerks' quarters, where "the clerks drank and sang daily"; the attendants, hating it and helpless, asked Cao Shen to stroll in the garden, hoping he would put a stop to it, whereupon he "had wine brought, set out seats and drank, and sang and shouted in answer to them."

Emperor Hui also came to doubt his neglect of business. Cao Zhu, Cao Shen's son, was a palace counsellor, and the emperor, thinking the chancellor's inaction meant "does he perhaps slight me?", told Cao Zhu to go home and ask his father privately and easily, "The late emperor has but newly left his ministers, the emperor is in the flower of youth, and you, sir, are chancellor, drinking daily and undertaking nothing — how is the empire to be cared for?" — with the charge not to say who had prompted it. Cao Zhu, on leave, urged him in his own words, and Cao Shen flew into a rage and gave him two hundred strokes with the cane, saying, "Get in and serve the emperor; the affairs of the empire are not for you to speak of." At court the emperor reproached him — "Why did you punish Zhu? It was I who set him to admonish you" — and Cao Shen, taking off his cap, made his apology, and then came the famous exchange: he asked whether the emperor thought himself the equal of the late emperor in sageliness and martial virtue, and the emperor said he could not presume to look to the late emperor; he asked whether the emperor thought him the equal of Xiao He, and the emperor said he was not. Cao Shen then said: "Your Majesty's words are right. The late emperor and Xiao He settled the empire, and the laws are already clear; now if Your Majesty lets his robes hang down and we keep to our offices and follow without losing what was set, is that not enough?" and the emperor said it was well. From this exchange came the phrase, "Xiao's rule, Cao's following."

The Fief and After

Cao Shen held the marquisate of Pingyang, and its line rose and fell repeatedly through the Former Han. After his death his son Cao Zhu succeeded, became imperial counsellor under the empress dowager Lü and was made a marquis again when Emperor Wen came to the throne, dying after twenty-nine years with the posthumous name Jing; his son Cao Qi succeeded, dying after seven years as marquis Jian; Cao Qi's son Cao Shi succeeded and married the princess of Pingyang, fathering Cao Xiang, and dying in his fief of illness after twenty-three years as marquis Yi; Cao Xiang succeeded, married the princess of Wei and fathered Cao Zong, dying after sixteen years as marquis Gong. In 91 BC Cao Zong, implicated in the rising of the heir apparent Liu Ju, was condemned and put to death, and the fief abolished. Afterwards the Han repeatedly provided for Cao Shen's sacrifices: under Emperor Ai an edict restored his family "to maintain the sacrifices to Cao Shen," and in the second year of Yuanshou the marquisate of Pingyang was renewed with a thousand households, increased by another thousand in the first year of Yuanshi; under Guangwu and Emperor He of the Later Han his descendants were again sought out, and in the third year of Yongyuan an edict ordered the grand herald to find near kin to continue the fief, after which the line of the marquis of Rongcheng was never again broken in Han times; after Wei replaced Han it continued until Wei's fall. The Records of the Three Kingdoms opens the annals of Emperor Wu with the words, "The great ancestor, Emperor Wu, was a man of Qiao in the principality of Pei, surnamed Cao, named Cao, styled Mengde, a descendant of the Han chancellor Shen" — so that Cao Shen was taken as the ancestor from whom the Wei imperial house descended; and Sima Qian listed the Caos among the hereditary houses of merit of the Former Han, under the title "the Hereditary House of Chancellor Cao."

Major Activities

Military Achievements

Cao Can was among the Han commanders with the greatest record of battlefield service. Sima Qian's Records of the Grand Historian states that he “received seventy wounds, attacked cities and seized territory, and had the greatest military merit.” The source credits him with conquering two states and 122 counties, capturing two feudal kings and more than ten senior officials. His major achievements included defeating the Sishui commandery inspector Ping, killing Li You, and helping capture Xianyang in the anti-Qin wars; pacifying the Three Qins, capturing King Bao of Wei alive, participating in the conquest of Dai, killing the Zhao commander General Qi, and helping pacify Qi during the Chu-Han wars. He repeatedly led assaults from the front and was one of Liu Bang's most experienced fighting commanders.

“Cao Followed Xiao's Rules”

After succeeding Xiao He as chief minister, Cao Can believed that the empire had only recently emerged from war and that ordinary people had been impoverished, so government should avoid unnecessary intervention. He followed Xiao He's laws and institutions without alteration and practiced the Huang-Lao ideal of government through non-action. He spent much time drinking and did not concern himself with minor administrative matters. When people came to lobby him, he often plied them with drink until they could no longer speak. He likewise tolerated small mistakes by subordinates and gave them opportunities to reform. When Emperor Hui expressed dissatisfaction, Cao Can used the comparison between Emperor Hui and Gaozu, and between himself and Xiao He, to argue that the laws had already been established by greater predecessors and later rulers needed only preserve them. The popular verse “Xiao He made the laws... Cao Can succeeded him, guarding them without loss” gave rise to the enduring expression “Cao followed Xiao's rules.” The policy is presented in the source as helping lay the foundation for the Rule of Wen and Jing.

Huang-Lao Government in Qi

When Cao Can became chief minister of Qi, the kingdom contained seventy cities and was already prosperous. He initially consulted many Confucian scholars about statecraft, but their competing views left him uncertain. After hearing that Master Gai of Jiaoxi was skilled in Huang-Lao thought, Cao Can invited him with great ceremony. Master Gai advocated quiet government and allowing the people to settle themselves. Cao Can accepted the advice, built a separate residence for Master Gai, and governed Qi largely by Huang-Lao principles. Qi was said to become well governed, and Cao Can earned a reputation as a “worthy chancellor.” The experience shaped his later policies as chief minister of Han.

Employment of Wei Bo

Wei Bo was poor in youth and recommended himself to Cao Can, then chief minister of Qi. Cao Can employed him as a retainer and later recommended him to King Daohui of Qi, Liu Fei, under whom Wei Bo became Interior Minister of Qi. During the later struggle against the Lü clan, Wei Bo forced Qi chancellor Zhao Ping to his death and mobilized troops to confine Liu Ze, King of Langya, thereby seizing military power and playing an important role in the conflict.

Later Honours and Judgments

The honours Cao Shen received in later ages go together with his "first in merit" in war and his government by "purity and non-action." In 782 Yan Zhenqing, master of ceremonies, proposed to Emperor Dezong of Tang that sixty-four ancient commanders be given posthumous rank and a temple with offerings, among them "Cao Shen, chancellor of Han and marquis of Pingyang"; and in 1123 the Song court, following the Tang precedent, gave a temple to seventy-two ancient commanders, Cao Shen among them. His tomb is said to lie west of Caojia village in Deping town, Shandong, known as the Caojia Han tomb, now about eight metres high and a hundred metres round, listed in 1933 in the Survey of Shandong's Ancient Sites and Monuments, and in 2013 declared a provincial cultural relic of the fourth batch; the tomb has been identified as of Han date, but whether it is Cao Shen's has not been established.

Later judgments of him turn chiefly on loyalty and good faith on the one hand and adherence to the law on the other. The eulogy says that he "held the jade tablet and the silk, taking cities and lands... was given the tallies and the fief, and in merit had no equal. He did not disturb the market and the courts, but kept pure and undertook nothing," and that "for nine years he governed Qi, caring only for the markets and the courts; for three years he stood in He's place, and lost nothing of his plans." Song writers called him a minister "by whom the ruler's virtue was nourished, the people's livelihood increased, and the altars of state steadied — a loyal and generous minister," and set him with Zhou Bo, Bing Ji, Di Renjie, Guo Ziyi, Pei Du, Lü Duan, Wang Dan and Han Qi as models of that kind; and Zeng Guofan, discussing the three immortalities of virtue, merit and words, put "merit, as with Xiao, Cao, Fang, Du, Guo, Li, Han and Yue" as the representative class. As for "Xiao's rule, Cao's following," later writers have generally approved it, holding that Cao Shen's policies let the people rest and recover, and that he was for that reason praised by the whole world.

Personal Relations

• Cao Zhu: son; later served as Censor-in-chief. Emperor Hui sent him to remonstrate with Cao Can, who punished him with two hundred lashes.
• Cao Xiang: descendant; led troops against the Xiongnu in the reign of Emperor Wu.
• Later descendants inherited the title Marquis of Pingyang during the Han.
• Xiao He: colleague in Pei County and close friend in youth; later relations deteriorated, but Xiao recommended Cao Can as his successor as chief minister.
• Master Gai: Huang-Lao scholar of Jiaoxi whom Cao Can invited at great expense and consulted on government.
• Wei Bo: talented man promoted by Cao Can and later Interior Minister of Qi.
• Liu Bang: leader of the Pei uprising, whom Cao Can followed from the beginning and under whom he became a founding meritorious official.
• Liu Ying (Emperor Hui of Han): emperor during Cao Can's term as chief minister; their exchange became the classic explanation of “Cao followed Xiao's rules.”
• Liu Fei (King Daohui of Qi): king of Qi whom Cao Can assisted.
• Han Xin: repeatedly campaigned with Cao Can, including the attacks on Wei, Dai, and Qi.
• Fan Kuai: fellow native of Pei who joined the uprising there.
• Zhou Bo: fellow native of Pei who joined the uprising.
• Xiahou Ying: fellow native of Pei who joined the uprising.
• Zhang Han: Qin commander whose forces Cao Can fought repeatedly.
• Li You: Qin commander defeated and killed by Cao Can at Yongqiu.
• King Bao of Wei: rebel feudal lord captured alive by Cao Can and Han Xin.
• Long Ju: Xiang Yu's general, defeated in the Qi campaign.
• Xiang Ji (Xiang Yu): principal opponent during the Chu-Han Contention.

Historical Assessment

Han and Contemporary Assessments

• Sima Qian wrote in the “Hereditary House of Chancellor Cao” in the Records of the Grand Historian that Cao Can's many military achievements were possible because he campaigned together with Han Xin, and that after Han Xin's destruction Cao alone among the marquises retained such a military reputation. Sima Qian also praised Cao's quiet government as chief minister, arguing that after the people had suffered Qin severity, Cao's policy of rest and non-interference brought widespread praise.
• A popular song declared: “Xiao He made the laws, orderly and uniform; Cao Can succeeded him, guarding them without loss. Bearing their purity and quiet, the people found unity and peace.”
• Ministers under Emperor Hui argued that Cao Can had “received seventy wounds, attacked cities and seized territory, and had the greatest military merit,” and therefore deserved first place in the merit ranking.

Wei, Jin, and Northern and Southern Dynasties

• Liu Xie referred to Cao Can's political methods in The Literary Mind and the Carving of Dragons, treating his quiet, non-interventionist rule as consistent with Daoist political thought.
• The source states that annotations to the Records of the Three Kingdoms quoting works such as the Wei Shu show later statesmen, including Cao Cao and Zhuge Liang, treating Cao Can's preservation of Xiao He's system as an example of government.

Tang and Song Periods

• Emperor Taizong of Tang was said to regard Cao Can as a model chief minister who could preserve established laws and bring peace to the people.
• The source states that Tang chief ministers such as Fang Xuanling and Du Ruhui also emulated aspects of Cao Can's quiet approach to government.
• Sima Guang's Comprehensive Mirror in Aid of Governance praised Cao Can for succeeding Xiao He without changing the existing arrangements and for strictly observing Xiao's regulations.
• In Record of Master Gai's Hall, Su Shi praised Cao Can for honoring worthy men and employing Huang-Lao principles in Qi, saying that after Cao followed Master Gai's advice, “Qi was indeed well governed.”

Ming and Qing Periods

• Li Zhi wrote in Cangshu that Cao Can's government was quiet and peaceful and that he understood the proper role of a chief minister.
• Wang Fuzhi argued in Du Tongjian Lun that Cao Can's preservation of Xiao He's policies reflected a deep understanding that an empire newly emerged from war should avoid excessive intervention and that this helped prepare the Rule of Wen and Jing.
• Zhao Yi, in Notes on the Twenty-Two Histories, held that Cao Can's military achievements were extensive but that his ability in government was even more difficult to attain.

Modern Assessments

• Qian Mu, in Outline of National History, characterized Cao Can as an able preserver of an established order whose continuation of Xiao He's policies allowed early Han society to stabilize and recover.
• Lü Simian, in History of the Qin and Han, argued that Cao Can's political ideas fit the needs of the time and that “Cao followed Xiao's rules” was not simple inactivity but rather acceptance of what already existed while removing excesses.
• Modern scholars generally regard Cao Can's policy of preserving Xiao He's system as a key component of early Han recovery and as groundwork for the Rule of Wen and Jing and later Han prosperity.