Three Kingdoms
Sima Yi, 司马懿 (A.D.179 - 251) Wei魏 Force Military Counsellor 中文详细
From Wikipedia, the free encyclopedia.


Simplified Chinese: 司马懿;
Traditional Chinese: 司馬懿
Pinyin: Sima Yi
Zi: Zhongda (仲達))

Sima Yi (179 - 251) was a military strategist of the Kingdom of Wei during the Three Kingdoms period. He is perhaps best known for defending the Kingdom of Wei from Zhuge Liang's northern campaigns. His success and subsequent rise in prominence paved the way for his grandson Sima Yan's foundation of the Jin Dynasty, which would eventually bring an end to the Three Kingdoms


Early Life


Sima Yi descended from the famous historian Sima Qian, author of the Shiji. He was one of 8 brothers, all of whom were famous due to their lineage. Each of them had a chinese style name ending with the character Da (達). Because of this, the brothers were known collectively as the "Sima 8 Das" (司馬八達).

Entering Service with Cao Cao

It is said that Cao Cao repeatedly requested the service of Sima Yi, and Sima Yi refused many times until at last he had no choice but to accept. However, according to the historical text The Brief History of Wei (魏略), Cao Hong, Cao Cao's younger cousin, requested the presence of Sima Yi in order to start a friendship with him, but the latter, not having a very high opinion of Cao Hong, feigned illness by carrying a cane in order to avoid meeting him. Cao Hong went to Cao Cao in anger and told him what had happened, after which Cao Cao directly requested the presence of Sima Yi. Then, and only then, did Sima Yi throw away the cane and enter Cao Cao's service.

As a Strategist

Early Career

In the year 219, the general Guan Yu of the Kingdom of Shu had progressed very far in his campaign in Jingzhou (荆州), defeating several armies and encircling Fan Castle (樊城), threatening to take it. There was much panic among Cao Cao and his advisors, with serious discussion of changing the capital to a further away location to be safer in the event of Fan Castle's fall. Sima Yi strongly opposed this idea, and instead proposed an alliance with the Kingdom of Wu in order to surround and defeat Guan Yu. His proposal was used, and was a great success. Guan Yu was defeated and order was restored to Wei.

When Cao Cao died, and was succeeded by Cao Pi, Sima Yi gained prominence and was used as an advisor more than he had been previously. When Cao Pi too passed away, Sima Yi was appointed as one of three regents to the young emperor Cao Rui, the other two being Cao Zhen and Chen Qun.

Battles Against Zhuge Liang

Before Zhuge Liang of the Kingdom of Shu began his first northern campaign, Sima Yi requested to be sent to the northeast region of China (西涼) to strengthen and expand the military power of the Kingdom of Wei there in order to defend from imminent attack. However, this region was rather remote, and it was strange for one of such high stature to personally request such an assignment, which caused many in Wei to be suspicious of his motives. Ma Su of Shu feared that if Sima Yi was successful in his plans to strengthen the area, Shu would be unable to attack Wei, and perhaps might be in danger of being attacked itself. Ma Su spread rumors that Sima Yi was attempting to gather forces to rebel against Wei, which eventually reached the ears of the already suspicious court. Sima Yi was then removed of military command and all other posts, although his life was spared.

With Sima Yi now effectively out of the picture, Zhuge Liang was free to begin his nothern campaigns. Taking advantage of the emperor's youth, many prominent members of the royal family with no real experience were promoted to positions in the military, and were put in defense of Wei. None of them were a match for Zhuge Liang, and Wei suffered numerous defeats.

The Wei court, now in panic in the face of the Shu armies closing in on their capital, turned to Sima Yi, recognizing that within Wei, only he could match Zhuge Liang. He was summoned to meet the emperor, Cao Rui, to officially accept command. At this time, Meng Da was planning a rebellion against Wei, and was in communication with Zhuge Liang, planning to coordinate his attacks and quickly destroy Wei. However, generals serving under Meng Da reported the plan to Sima Yi just as he was gathering an army to meet the emperor. Instead of going first to the emperor to be formally returned to command, he instead quickly moved on Meng Da and easily defeated his rebellion. Having done this he apologized to the emperor for acting without authority, but because of his accomplishment he was forgiven and was able to go to the front to battle Zhuge Liang.

In defending against Shu's northern expeditions, he knew that the enemy's army required constant supplies from their country, carried over a long distance. Seeing this weakness, his strategy relied on defending very cautiously and attacking Shu's supply line weakness whenever possible. His strategy was successful, and he was able to prevent Zhuge Liang from advancing any further.

Late Career

After Zhuge Liang

After Zhuge Liang's death, Shu's northern expeditions ceased for the time being, and peace returned to the Kingdom of Wei. The emperor, Cao Rui was now an adult and taking advantage of the peace he turned to palace building, costing extravagant amounts of money and alienating his ministers and people. In this environment, Gongsun Yuan, a powerful warlord, rebelled. Sima Yi quickly ended the rebellion, bringing him even greater prestige.

Cao Rui died not long afterward and the next emperor, again very young, Cao Fang ascended to the throne. This time two regents were appointed, Sima Yi, and Cao Shuang, the son of Cao Zhen.

Friction with Cao Shuang

In the year 241, Zhu Ran of the Kingdom of Wu had Fan Castle (樊城) under siege. Sima Yi personally went to lift the siege, and succeeded in driving the attackers away. He then succeeded in defeating Zhuge Ke of Wu in the year 243. In contrast to this, Cao Shuang's attempts to attack the Kingdom of Shu ended in failure.

Cao Shuang was very jealous of Sima Yi's great power and prestige, and sought total control over the Kingdom of Wei. At the advice of an advisor, he persuaded the emperor to promote Sima Yi to personal instructor to the emperor. Although among the highest of positions a person could be given, it was an honorary position only and completely without any military or political authority.

Sensing danger, Sima Yi retired from his position in 247, citing illness as the reason. Sensing a ploy, Cao Shuang sent an advisor to visit Sima Yi, to check whether or not he was truly ill. Sima Yi, then advanced in aged, pretended to be senile. Cao Shuang's advisor completely believed the act, and Cao Shuang finally felt safe that he had no challenge to his power. Sima Yi bided his time, and when Cao Shuang, who loved hunting, left the capital Luoyang in 249 Sima Yi sprung into action. He moved on the imperial palace with an army and convinced the emperor's mother to give an order to arrest Cao Shuang in order to save the kingdom from his irresponsible government. Cao Shuang and his allies, with an imperial order declaring them rebels, had no leg to stand on and surrendered, expecting to be spared. Instead, Sima Yi executed them all.

Solidification of Power

With complete power over the Kingdom of Wei now in his hands, Sima Yi became Prime Minister. In 251, Wang Ling of Wei convinced Cao Bao to attempt a coup d'etat agaist Sima Yi, but the plot was discovered and Sima Yi went on the offensive. Knowing that they would be killed, the two commited suicide. In order to prevent any more rebellions, Sima Yi put the entire Cao clan under house arrest in Ye. He put them under watch and from that point on prevented any of them from having any contact with one another.

With the entire royal family of Wei out of his way, Sima had effectively made the kingdom's nominal rulers irrelevant. However, instead of declaring himself emperor and founding a new dynasty, he would leave the problem to his descendants. Later in the year, he passed away. When his grandson Sima Yan founded the Jin Dynasty, Sima Yi was posthumously named an emperor.


Direct Descendants

  • Sima Shi (司馬師)
  • Sima Zhao (司馬昭)
  • Sima Yan (司馬炎) (Grandson, founder of the Jin Dynasty)
  • Sima Gan (司馬幹)
  • Sima ?? (司馬伷)
  • Sima Liang (司馬亮)
  • Sima Jing (司馬京)
  • Sima Jun (司馬駿)
  • Sima ?? (司馬榦)
  • Sima ?? (司馬肜)
  • Sima Lun (司馬倫)

Other Family


  • Sima Qian (司馬遷) (famous historian)


  • Sima Lang (司馬朗)(older brother)
  • Sima Fu (司馬孚) (younger brother)
  • Sima Kui (司馬馗) (younger brother)
  • Sima Xun (司馬恂) (younger brother) S
  • ima Jin (司馬進) (younger brother)
  • Sima Tong (司馬通) (younger brother)
  • Sima Min (司馬敏) (younger brother)