|General of Cao Wei|
|Style name||Zidan (Chinese: 子丹; pinyin: Zǐdān; Wade–Giles: Tzu-tan)|
|Posthumous name||Marquis Yuan (Chinese: 元侯; pinyin: Yuán Hóu; Wade–Giles: Yüan Hou)|
Cao Zhen (died 231), style name Zidan, was a military general serving under the warlord Cao Cao in the late Eastern Han Dynasty. He served the state of Cao Wei during the Three Kingdoms period. He was also a distant nephew of Cao Cao, though the latter treated him like a son. Cao Zhen participated in many campaigns against the forces of Liu Bei and Sun Quan. From 227 onwards, he was very much involved with successfully repelling the frequent invasions led by Zhuge Liang.
Service under Cao Cao 
According to the Records of Three Kingdoms, Cao Zhen was a distant nephew of Cao Cao. In 190, when Cao Cao was raising an army to join the coalition against Dong Zhuo, the tyrannical warlord who held Emperor Xian hostage, Cao Zhen's father, Cao Shao, heeded the call but was killed before he could join Cao Cao. The Brief History of Wei (魏略) by Yu Huan, however, says Cao Zhen was originally surnamed Qin (秦). Cao Zhen's father, Qin Bonan, had long been friends with Cao Cao. In 195, as Cao Cao was fleeing from rebels, he hid in the Qin's. When rebels asked for the whereabouts of Cao Cao, whom they did not recognize by face, Qin Bonan claimed to be the man and was slain.
Either way, Cao Cao took in the young Cao Zhen, whom he raised as his own son. He had Cao Zhen resided with his future successor Cao Pi and another distant nephew Cao Xiu. The three of them would travel with five of the seven scholars of Jian'an, including Wu Zhi, Liu Zhen (刘桢), Xu Gan (徐干), Ying Yang (应玚), and Chen Lin (陈琳) from time to time. Due to his chubby shape, he was often ridiculed by his friends, especially by the famous jester, Wu Zhi. Unfortunately for him, Cao Zhen's distant uncle, Cao Hong, was also a compulsive prankster who never failed to "show concern" on his nephew's size problem. As Cao Zhen did not have power at the time, he could only bear a furtive displeasure against jokes revolving around his weight, but his muffled wrath would keep accumulate to a point where it nearly broke out into a duel between him and Wu Zhi years later (see Appraisal section below). Probably had have enough from his influential "friends", Cao Zhen remained most intimate with lower characters like his clansman Cao Zun (曹遵) and general Zhu Zan (硃赞).
Ironically, he was specifically ordered to serve as a captain in the highly mobile Tiger and Leopard Cavalry, despite his health problem. Henceforth Cao Zhen followed Cao Cao in a series of battles without noted accomplishment until the war with southwestern warlord, Liu Bei. In 219, during the struggle for Hanzhong, the western commander of Cao Cao, Xiahou Yuan, was defeated and killed in the Battle of Mount Dingjun, Cao Zhen was charged with overseeing the retake of Yangping Pass (阳平关) by forces led by Xu Huang. He commissioned his subordinate to defeat Gao Xiang in their task, but Liu's forces occupied nearly all strategic positions and refused engagement. Facing logistical difficulty, Cao Cao personally led a force to pull Zhang He out from encirclement, and Cao Zhen was sent to escort Cao Hong from Wudu. After Cao Zhen had merged his force with that of Cao Hong's, they retreated to Chenchang, where Cao Zhen stationed his troops to prevent possible attack from Shu.
As a Wei commander 
Failure against Sun Quan 
After Cao Pi succeeded Cao Cao in 220, Cao Zhen was made General who Guards the West (镇西将军) and charged with the defense of Yong Province (雍州) and Liang Province (凉州). When he was recalled to the capital Luoyang in 222, he was promoted to "Grand General of the Supreme Army" (上军大将军) and given command of all domestic and foreign military affairs, making him arguably the military paramountcy. In the same year, Cao Pi launched his three-pronged attack on the eastern warlord, Sun Quan. Cao Zhen, together with Zhang He, Xu Huang, and Xiahou Shang, was ordered to lay siege upon Jiangling fortress, which was guarded by Zhu Ran's mere 5000 soldiers. Although they had defeated some enemy relief forces and taken some enemy camps, Zhu Ran had been playing a staunch defense and destroyed most of Cao Zhen's siege engines. The war turned out to be a prolonged one, resulting in an epidemic outbreak, which plagued both belligerents, and the invaders became demoralized and dissipated. One night, Zhu sneaked out and raided some camps of Cao-Wei, hampering the besiegers' fighting spirit further. As the other two prongs failed, Cao Zhen also led the army back to Wei territory. As a result of the failure, Cao Zhen was transferred from "Grand General of the Supreme Army" (上军大将军) to "Grand General of the Central Army" (中军大将军).
Successes over Zhuge Liang 
In 227, Cao Rui succeeded the throne of Cao Wei and Cao Zhen was promoted to Supreme General (大将军). Believing the young Cao Rui was inexperienced, Zhuge Liang, Chancellor of Shu Han, launched the first of his Northern Expeditions against Cao Wei shortly after Cao Pi died. Three commanderies of the distant Longyou soon defected to Zhuge; thus, Cao Zhen hurriedly led his troops to Mei (郿), near Chang'an and Chencang (陈仓), in fear Zhuge would attack either city. However, the enemy attacked the garrison atop Mount Qi. An enemy force commanded by Zhao Yun appeared at Qi Trail, hindering Cao Zhen from reinforcing Mount Qi, where Zhuge Liang personally laid a siege. With better trained soldiers, Cao Zhen defeated Zhao Yun, who was only given weaker troops by the Shu Chancellor, forcing the loser to retreat, but gave up pursuit on the latter. Then, the Supreme General ordered Zhang He to locate and cut Zhuge's supply line. At the time Zhang completed his mission, Zhuge was still struggling to take over Mount Qi, which was actually not heavily guarded; when Zhuge Liang got wind of what happened, he gave up the expedition and forced 1,000 households of West County to move to Hanzhong.
Observing Zhuge's failure at Mount Qi, Cao Zhen had deduced the former would attack Chencang next time, so he ordered Hao Zhao and Wang Sheng to fortify that city. Cao's prediction was accurate, but he did not expect the Shu Chancellor would launch another large scale assault just one year later. At the time, Hao Zhao only had 1,000 soldiers under command, while Zhuge Liang had brought 100,000 men and a range of siege weapons and projectiles to the battlefield. Nevertheless, Hao Zhao managed to destroy most of Shu's siege weapons and forced the invaders to turn back. Cao Zhen received an increase on salary due to his prior advice. For the next few years, Cao successfully fended off every invasions from Zhuge.
In 230, Cao Zhen headed for Luoyang for an audience with the emperor, during which he was made the Minister of Defense. He then proposed a shift from defensive to offensive stance, with a multi-pronged attack on Hanzhong, primary base of Zhuge Liang's intrusions. His proposal was accepted and in the same year, Cao Zhen led a force towards Hanzhong taking a route south of the Ziwu Trail (子午道), while Sima Yi led another force west along the Han River. The two forces were slated to converge at Nanzheng (南郑), southwest of Hanzhong. However, the plan was thwarted by heavy rainfall, which lasted for more than a month and rendered the mountainous paths muddy, interfering the military advance.
The Minister of Defense fell sick on his journey back to Luoyang, where he died a year later. He was given the posthumous title of Marquis Yuan (元侯), literally meaning the marquis of origin. His son, Cao Shuang, would later become the regent of Wei and monopolize the imperial court, until the incident at Gaoping Tombs.
Despite his obesity, Cao Zhen was well known for his archery. The Records of Three Kingdoms recorded a hunting trip during which the young Cao Zhen was chased by a tiger. Turning around, he fired an arrow and felled the beast with one shot. He was also respected among his subjects and troops for his humility and generosity. During the excursions, Cao would share the labor of his men. When the treasury ran short of the wages due, he would make it up with his own wealth.
In fiction 
Cao Zhen's importance begins to rise in Chapter 91 as Zhuge Liang launches his Northern Expeditions against Cao Wei. However, his contributions in the series of battles and maneuvers for the next eight chapters were largely played down by the author in an effort to accentuate the resourcefulness of Sima Yi. Luo Guanzhong even attributed Cao Zhen's death to his failure to heed Sima Yi's forewarning of a Shu offensive.
In Chapter 100, Sima Yi warned that Shu troops would come within ten days for Mount Qi, a strategic point which would allow further incursions into the heart of Cao Wei, but Cao Zhen did not believe his words. The two then held a bet. Each leading a half of the army, they guarded the valleys to the east and west of the mountain.
Cao Zhen was only half-hearted in preparing for an assault. Seven days later, however, scouts spotted a small number of Shu soldiers approaching the valley. Cao Zhen then sent his aide Qin Liang (秦良) with 5,000 troops to survey the situation. As Qin Liang was drawn deeper into the valley, his force was ambushed and eradicated by a Shu force under Liao Hua and Guan Xing. Disguising themselves in the clothing and armor of the Wei soldiers, Zhuge Liang's men then infiltrated the enemy's camp.
Meanwhile, Sima Yi had encountered and defeated a subdivision of the Shu force under Wei Yan but reports from Cao Zhen claimed that no enemies were sighted on the other side. Fearing for the worse, Sima Yi drew a force and came for Cao Zhen's camp. True enough, the Shu troops and the infiltrators had launched a surprise attack, seizing Cao Zhen's men. Sima Yi arrived in time to ward off the attack, but Cao Zhen felt so insulted by the defeat that he fell ill.
Zhuge Liang then wrote Cao Zhen a letter full of insulting remarks, upon reading which the latter was so filled with rage that he died that very night in camp. Sima Yi then had Cao Zhen's body sent back to the capital Luoyang for burial.
- Father: Cao Shao (曹邵), joined Cao Cao's forces in the early 190s, killed by Huang Wan (Governor of Yu Province)
- Cao Shuang, oldest son, ruled as regent during Cao Fang's reign, fell from power in the Incident at Gaoping Tombs, killed by Sima Yi after surrendering
- Cao Xi (曹羲), served as a general during Cao Shuang's regency, killed by Sima Yi after Cao Shuang's surrender
- Cao Xun (曹訓), served as a general during Cao Shuang's regency, killed by Sima Yi after Cao Shuang's surrender
- Cao Ze (曹則), granted a marquis title
- Cao Yan (曹彥), granted a marquis title
- Cao Ai (曹皚), granted a marquis title
- Cao Xi (曹熙), grandnephew, continued Cao Zhen's family line, granted title of Marquis of Xinchangting in the 250s
Appointments and titles held 
- Marquis of Lingshou (靈壽亭侯)
- Lieutenant General (偏將軍)
- General of Central Resolute (中堅將軍)
- Central Commander of the Army (中領軍)
- Protector of the Army Who Attacks Shu (征蜀護軍)
- General Who Guards the West (鎮西將軍)
- Marquis of Dong (東鄉侯)
- Senior General of the Upper Army (上軍大將軍)
- Senior General of the Central Army (中軍大將軍)
- Geishizhong (給事中)
- General-in-Chief (大將軍)
- Marquis of Shaoling (邵陵侯)
- Grand Marshal (大司馬)
- Marquis Yuan (元侯) - granted to Cao Zhen posthumously
See also 
- de Crespigny, Rafe (2007). A biographical dictionary of Later Han to the Three Kingdoms (23–220 AD). Brill. p. 50. ISBN 978-90-04-15605-0.
- Note that the "seven scholars of Jian'an" is not an official title, and the membership of this group is disputed.
- (以真为征蜀护军，督徐晃等破刘备别将高详於阳平。太祖自至汉中，拔出诸军，使真至武都迎曹洪等还屯陈仓。). SGZ. Biography of Cao Zhen.
- (诸葛亮围祁山，南安、天水、安定三郡反应亮。) SGZ.
- (亮出军，扬声由斜谷道，曹真遣大众当之。亮令云与邓芝往拒，而身攻祁山。) SGZ.
- (云、芝兵弱敌强，失利于箕谷，然敛众固守，不至大败。) SGZ.Biography of Zhao Yun.
- (亮拔西縣千餘家，還於漢中，戮謖以謝眾。) SGZ. Biography of Zhuge Liang.
- (真以亮惩于祁山，后出必从陈仓。) SGZ.
- Chen Shou (2002). Records of the Three Kingdoms, Volume 9, Biography of Cao Zhen. Yue Lu Shu She. ISBN 7-80665-198-5.
- Luo Guanzhong (1986). Romance of the Three Kingdoms. Yue Lu Shu She. ISBN 7-80520-013-0.
- Lo Kuan-chung; tr. C.H. Brewitt-Taylor (2002). Romance of the Three Kingdoms. Tuttle Publishing. ISBN 0-8048-3467-9.