Strategic and tactical analysis of Zhuge Liang's three Northern Expeditions against Cao Zhen.
The First Northern Expedition
Strategy: Encroach on Yongliang
Tactics: Plotting against Meng Da, attacking the west with sound
Battle results: relocating part of the population of the three counties of Longxi and surrendering Jiang Wei
Zhuge Liang first wrote a letter against Meng Da, who was too defensive of Xincheng, and then revealed the news of his rebellion to Sima Yi, who led an army to recruit Meng Da, and Zhuge Liang promised to immediately lead an army to support meng da, so that Meng Da would stick to help. However, in fact, Zhuge Liang did not march into the new city, but divided his troops into two roads: one way Zhao Yun led a partial division into Xiegu Valley, and the other way led the main force to qishan. When the Wei general Cao Zhen led a large army to confront Zhao Yun at Jigu Valley, Zhuge Liang raided Qishan and captured the three counties of Longxi almost without bloodshed, and the purpose of the Northern Expedition choosing to march from Qishan was to seize the Longxi region of the Wei state, practicing the "encroachment on Yongliang" mentioned in the Hanzhong Policy.
Through the strategy of attacking the west from the east, Zhuge Liang's plan was basically realized, and the Longxi Commandery Shouyou Chu, who was still resisting, also made a promise to surrender within a month of resisting the Wei reinforcements. Unexpectedly, Ma Mo was defeated by Zhang Gao at the street pavilion, Zhuge Liang was forced to retreat, and the three counties captured by the First Northern Expedition were regained. However, this Northern Expedition was not without results, Zhuge Liang still moved some of the population to compensate for the loss of troops, and surrendered jiang Wei, the pillar of the late Shu Han Dynasty.
Second Northern Expedition
Strategy: Luring the Wei army back to help and alleviating the pressure on Eastern Wu
Tactics: Encircle Wei and save Zhao
Results: Successfully attracted the main force of the Wei army and killed Wang Shuang
Eastern Wu Lu Xun destroyed sima Cao Xiu of the State of Wei at the Stone Pavilion, and the State of Wei was shaken. Probably believing that Zhuge Liang's northern expedition would not come again, and that the threat of the State of Wei was only Eastern Wu, so the general Cao Zhen led a large army to attack Sun Quan, vowing to avenge Cao Xiu, and it is recorded that Cao Zhen had expected Zhuge Liang to attack Chen Cang, but this record actually has a big loophole:
One: Since Cao Zhen expected Zhuge Liang to attack Chen Cang, and once Zhuge Liang captured Chen Cang, Bing Feng would point directly at Chang'an. Chen Cang's strategic position was so important, why didn't Cao Zhen send heavy troops to defend?
Second: Since Zhuge Liang's attack was expected by Cao Zhen, why did Cao Zhen already go to the Eastern Front and hastily return to defense? So tired of running for his life to support Chen Cang?
Therefore, the author believes that saying that Cao Zhen expected Zhuge to attack Chen Cang was nothing more than a boast of the horse's hindsight.
In a letter to Zhuge Jin, Zhuge Liang mentioned Chen Cang's plan to march:
There is a small valley in Suiyang, although the cliffs are extremely heavy, the streams are longitudinal, and it is difficult to use the march. Waiting for the traffic, the road leads to entry. Now the former army cut this road, in order to Chen Cang, enough to pull the thief's momentum, so that the eastward marchers could not divide the troops. -----------------
The letter reveals zhuge liang's purpose in attacking Chen Cang: to encircle Wei and save Zhao. Attracting the main force of the Wei army to return to help and alleviating the pressure on Eastern Wu, so when Cao Zhen supported Chen Cang, Zhuge Liang's purpose had already been achieved, which also explained why Zhuge Liang's second Northern Expedition was fought for less than a month, and there was not enough grain and grass to retreat: Zhuge Liang's purpose was not to capture Chen Cang, there was not much grain and grass at all, in fact, when Cao Zhen's troops arrived at Chen Cang, Zhuge Liang led the army to retreat, and this timing was very accurate. The grain and grass did not have to be finished early, and it was not finished late, but Cao Zhen ran out as soon as he came. Cao Zhen sent Wang Shuang to pursue, but was killed by Zhuge Liang, many people said that Zhuge Liang's northern expedition was a failure, but although Zhuge Liang did not conquer Chen Cang (the purpose of the people was not originally this), but he successfully attracted the main force of the State of Wei, achieved the strategic purpose, and also defeated Wang Shuang, how can it be considered a failure?
The Third Northern Expedition
Strategic objectives: Capture Wudu, Yinping County, and break Guo Huai.
Tactics: Avoid the real and the virtual, surround the point to help
Battle results: capture of Wudu, Yinping County, and forced guo Huai to retreat
Almost at the same time as Zhuge Liang and Chen Cang retreated, Chen Shi led an army to capture the Wu capital of the State of Wei, The Second County of Yinping. The State of Wei, the capital of Wudu Yinping, had almost no garrison, and Cao Zhen was again attracted to Chen Cang by Zhuge Liang, so Chen Shi captured the second county without pressure. Guo Huai led an army to meet Chen Shi, but learned that Zhuge Liang had appeared in Jianwei and retreated in a hurry.
It turned out that Zhuge Liang not only wanted to capture the second county, the bigger plan was to encircle the point to help, attract Guo Huai to attack to defeat it, of course, Guo Huai saw through Zhuge Liang's plan, retreated in advance, and was not wrapped in dumplings.
Judging from these three Northern Expeditions, Zhuge Liang's military ability was definitely a first-class strength among the Three Kingdoms.
bibliography:
Romance of the Three Kingdoms