Jiang Wei's Northern Expeditions

Jiang Wei's Northern Expeditions refer to a series of nine military campaigns launched by Shu Han general Jiang Wei against the rival state of Cao Wei from 247 to 262 during the Three Kingdoms period of Chinese history. Each expedition was aborted eventually due to inadequate food supplies or battlefield losses. Jiang Wei's campaigns drained Shu's already limited resources, and led to the eventual downfall of Shu in 263.

First expedition: Battle of Tao River
In 247, Jiang Wei led some troops to quell a minor uprising by local tribes in Pingkang (平康), Wenshan (汶山). After which, he invaded Longxi (隴西), Nan'an (南安) and Jincheng (金城) where he fought Guo Huai and Xiahou Ba west of the Tao River. Xiahou Ba fled and the army scattered.

Guo Huai dispatched Deng Ai to guard the northern coast of Baishui. Three days later, Jiang Wei dispatched Liao Hua to camp at the southern coast of Baishui as a ruse while he intended to launch a sneak attack at Taocheng. However, Deng Ai saw through his plans and proceeded to occupy Taocheng before Jiang Wei. He attacked and defeated Liao Hua. Deng Ai later, attempted to shield his defence and injured Liao Hua, thus forcing him to flee.

In anger, Jiang Wei attacked Taocheng with almost everything he had. He used his rams and towers to destroy Taocheng so he could destroy Deng Ai. Suddenly, Sima Zhao sent his ambush team to rescue Deng Ai. Gao Cheng taken Jiang Wei's main camp at Baishui, forcing Jiang to retreat. Jiang Wei re-assembled his units and launched a second siege at Qucheng.

Second expedition: Battle of Qucheng
In 249, Jiang Wei constructed two forts at the Qu mountains and dispatched troops to defend them. In addition, Jiang Wei took the native people (from the Di and Qiang tribes) as hostages and forced them to obey his orders. Seeing this, Chen Tai advised his superior, Guo Huai, that it would be a good opportunity for them to launch an attack on the forts given that the distance between the forts and Shu's track was far, and the natives were resentful of forced labor under Shu. Guo Huai agreed with Chen Tai and sent him to attack the Shu defending army under Xu Zhi. At the same time, the governor of Nan'an, Deng Ai, was dispatched to lay siege to the forts. As they were speaking, Jiang Wei stole enemy supplies for aid.

Chen Tai managed to cut the food and water supply chains to the forts but was surrounded by Shu soldiers who came out for a counteroffensive. Subsequently, Jiang Wei led his main forces to break the siege and met up with Chen Tai at the rear of Bull Head Mountain. Instead of engaging Jiang Wei's troops, Chen Tai stalled Jiang Wei for time to let Guo Huai cut off Jiang Wei's supply and retreat route at Yao River. Guo Huai agreed and proceed as planned. Jiang Wei found out the maneuvers of the Wei armies and realized that there was a competent commander in the Wei's ranks. Despite the unfavorable situation, Jiang Wei refused to retreat and on seeing that, the soldiers at the two forts pretended to surrender to Wei.

Meanwhile, Chen Tai saw through the fake surrender and battled the enemy troops. Jiang Wei met Chen Tai again and this time they dueled. Chen Tai forced Jiang Wei to retreat back to Hanzhong.

Third, fourth, and fifth expedition
In 249, Jiang Wei launched his third invasion and was defeated.

In 253, Jiang Wei set up a coordinated attack with Zhuge Ke to attack Wei on two fronts: Shu on the west in Nan'an and Shu's ally Eastern Wu on the east at Hefei. Jiang Wei attacked the key border city of Didao as Zhuge Ke launched a massive attack on Hefei. The Wei regent Sima Shi knew the Wu army to be the more serious threat and led the main Wei force to the eastern front, while sending a smaller unit to relieve Didao. The first sign of what would eventually recur, Jiang Wei, while besieging Didao, ran out of food supplies and had to withdraw. Eventually, Sima Shi's forces dealt a crippling defeat to Zhuge Ke.

However, Jiang Wei resumed his attack very soon, and led tens of thousands of Shu soldiers to venture into Wei territory again. He bypassed Shiying (石營) and Dongting (董亭), and laid siege on Nan'an. Chen Tai reinforced Nan'an in time, and Jiang Wei lifted the siege due to logistical consideration. Guo Huai then drove back Jiang Wei's forces out of Wei's domain.

Sixth expedition: Long（陇）Campaign
In 254, after Li Jian (李簡), the county magistrate of Didao, secretly declared that he would defect, Jiang Wei again attacked Longxi, and took the city of Didao. However, a local force led by Xu Zhi managed to deal considerable damage to the enemy and slew Shu general Zhang Ni (張嶷, sometimes transliterated as Zhang Yi). However, Zhang Ni's desperate fight also inflicted a devastating damage to Xu Zhi's army, forcing the latter to retreat and await reinforcements. Shu forces thus gained some footholds on the Long region and battles went on and off for some time, and Jiang Wei forced the residents in Didao, Hejian (河間) and Lintao (臨洮) to retreat with him to Longxi upon the arrival of Guo Huai. At this juncture, Zhang Yi (張翼) attempted to convince Jiang Wei to declare victory and return to Hanzhong as he witnessed the death of his colleague, Zhang Ni, and feared the sacrifice would go in vain if the campaign was to be continued. Jiang Wei refused, and deemed the defeat of Xu Zhi (who actually was just a low ranking military officer) as a major success, not realizing such a deed was accomplished by Zhang Ni's sacrifice.

In the summer of 255, Jiang Wei and Xiahou Ba (who had defected to Shu) attacked Didao again in three different directions aiming for Mount Qi, Jincheng and Shiying. Jiang Wei was successful in his initial battles against the Wei Inspector of Yong Province, Wang Jing (王經), west of the Tao River, nearly annihilating Wang's troops, leaving around 10,000 troops to defend Didao. Wang Jing requested Chen Tai to dispatch troops to defend in all three directions Jiang might attack. However, Chen Tai did not think that Jiang Wei would split his forces into three, so he ordered Wang Jing to defend Didao and only launched an attack when Shu armies arrived and an opportunity arose. Then, Chen Tai personally led some troops to defend Chencang. However, Wang Jing disobeyed Chen Tai's order and proceeded to attack the enemy on his own. On hearing that, Chen Tai knew that something disastrous would happen and hastily led his armies to reinforce Wang Jing.

Chen Tai reorganized the defeated troops in preparation for a counteroffensive. Chen Tai mentioned although Jiang Wei was victorious, he did not seize the opportunity to attack eastward in order to capture Wei's food supplies at Liyang. Zhang Yi again tried to persuade Jiang Wei to stop his campaign at this point; unfortunately, Jiang refused. Rather, Jiang Wei besieged Didao again and Shu morale was affected due to continuous campaign and fatigue. Jiang Wei and Chen Tai's forces stayed in a stalemate throughout the winter. One night, Chen Tai led his troops to a mountain south of Didao, and instructed his troops to raise torches. The Wei troops defending at Didao saw that and their morale increased tremendously. Shu's troops besieging Didao were badly affected by the display put up by Chen Tai and a portion of the Shu forces was dispatched to attack Chen's army and they were badly defeated by Chen due to his capitalization of strategic points for defense. As a result, the Shu armies were forced to lift the siege and retreat; thus Didao was saved. However, Jiang, who unwilling to abort the campaign, camped at Zhongti.

Seventh expedition: Battle of Duan Valley
In 256, Jiang Wei had arranged for Hu Ji to assist his expedition aiming for Mount Qi. However, Hu Ji broke his promise and did not arrive as planned. When Jiang Wei heard that Deng Ai was fully prepared, he decided to attack Nan'an and left his Qishan camp with patrol decoys carrying his insignia. Deng Ai, who saw through the deception, left Chen Tai to attack Jiang's Qishan camp and made forced marches to Nan'an. Deng position his army at the peak of Mount Wucheng, an advantageous position to the city of Nan'an. Jiang Wei launched failed three sorties to take it. Later that evening, he consulted Xiahou Ba. Xiahou Ba told him to take Shanggui, Nan'an's grain depot, cutting Nan'an from supplies and let the city starve to death. Taking the Xiahou's advice, Jiang Wei led crack generals and troops to Shanggui via Duan Valley. However, Deng Ai was a step ahead of him. He send his son, Deng Zhong with his company of troops, lying in ambush at the same valley. As a result, Jiang Wei was badly defeated and suffered heavy casualties at Duan Valley. Xiahou Ba rescued Jiang Wei from the trap and reported to him that the Qishan camp has been overrun by Chen Tai and his troops. Due the destruction of the Qishan camp, Jiang Wei ordered his army to retreat to Hanzhong. Chen Tai ambushed and encircled Jiang Wei's fleeing army. Zhang Ni came to Jiang's aid to break the encirclement with cost of his own life. Jiang Wei petitioned to the Shu court to demoted him to Rear General for his defeat. It dealt him a major loss that would cause the Shu citizens resent his regency.

Eighth expedition: Battle of Mang River and ninth expedition: Battle of Taoyang
In 257, when Zhuge Dan rebelled against Wei, Jiang Wei attacked Chenling, advancing all the way to Mangshui, and a stalemate resulted at Weishui, but Jiang could not induce Wei forces, commanded by Deng Ai and Sima Wang. In 258, Jiang Wei withdrew after Zhuge Dan was defeated.

In 262, despite Liao Hua's opposition, Jiang Wei, attacked Wei again, targeting Taoyang, but was defeated by Deng Ai, and withdrew to Tazhong. In Romance of the Three Kingdoms, Xiahou Ba was killed here by Wei forces who ambushed him in a narrow mountain pass.

Aftermath
After Jiang Wei's continued failures in his invasions, the people of Shu resented him. Shu resources were almost drained and this gave Wei an opportunity to attack and eliminate Shu. Zhong Hui and Deng Ai invaded Shu at two points. Jiang Wei resisted Zhong Hui's attack, but Liao Hua was defeated by Deng Ai, and after the defeat of Zhuge Zhan at Mianzhu Pass, Shu was lost. In 263, the Shu emperor Liu Shan surrendered to Deng Ai, and Jiang Wei was ordered to surrender his troops to Zhong Hui.

Modern references
Some of the expeditions are featured as playable stages in the seventh installment of Koei's Dynasty Warriors video game series. A notable difference is the battles of the expeditions are out of order (e.g. Battle of Tao River served as the third invasion), and only four of the invasions are depicted.