Wei Yan (pronunciationⓘ) (died c. October 234[1]), courtesy name Wenchang, was a Chinese military general and politician of the state of Shu Han during the Three Kingdoms period of China.

After Zhuge Liang's death in c. September 234, Wei Yan was executed by another Shu general, Ma Dai, for alleged treason.

[2] The campaign met early success with the quick death of Gao Pei and Yang Huai and the later occupation of the passes, followed by the defeat of Liu Zhang's reinforcements at Fu County.

One year later, Wei Yan and Liu Bei finally captured Luocheng, then surrounded and occupied Chengdu together with Zhuge Liang, Zhang Fei along with others.

[4][a][b] As Wei Yan has made several contributions in the conquest of Yi Province, Liu Bei promoted him to the rank of General of the Ivory Gate (牙門將軍).

[8] However, much to everyone's surprise, Liu Bei chose Wei Yan instead and appointed him as General Who Guards Distant Lands (鎮遠將軍) and acting Administrator of Hanzhong (漢中太守).

The ancient text I Ching described this strategy as a particularly designed fortification which laid numerous military garrisons surrounding the outskirt and trail exits linking to Hanzhong.

[2][17] During this campaign, Wei Yan always requested to lead a separate detachment of 10,000 troops, take a different route through the Ziwu Valley (子午谷) and rendezvous with the Shu main army at Tong Pass (潼關; in present-day Tongguan County, Shaanxi).

[22] During the same year, he also assisted another Shu general Wu Yi in attacking Nan'an Commandery (南安郡; southeast of present-day Longxi County, Gansu) where they scored another victory against a Wei army led by Fei Yao.

[32] Whenever they got into heated quarrels, Wei Yan often drew his sword and brandished it in front of Yang Yi, who sobbed as tears rolled down his cheeks.

[33] Zhuge Liang was upset by the lack of harmony between Wei Yan and Yang Yi, but was unwilling to side with either of them because he appreciated the talents of both men.

The officials serving in the Imperial Chancellor's Office may bring his body back (to Chengdu) for burial, but I should remain behind to lead the army to attack the enemy.

[37] He then sent his subordinate to meet Yang Yi and the others, but was shocked to discover that all units were preparing to retreat in accordance with Zhuge Liang's final orders.

In the meantime, Yang Yi ordered his men to cut down trees to rebuild the gallery roads, and his troops marched day and night to catch up with Wei Yan.

Wang Ping shouted at Wei Yan: "His Excellency (Zhuge Liang) had just died and his body had yet to turn cold, and now you dare to do something like this!"

[39] Ma Dai executed Wei Yan, brought his head back, and threw it in front of Yang Yi.

[39] They had travelled for about 10 li (about three miles) when they received news of Wei Yan's death; they then turned back and returned to Chengdu.

[47] Yi Zhongtian analysed and criticised Wei Yan for not grasping the political-economic reasons behind Zhuge Liang's expeditions and his extreme caution.

[47] As the smallest and weakest amongst the Three Kingdoms, Shu would be the first one to be targeted, hence it had to launch preemptive attacks to intimidate its opponents, to expand its territory, and to improve its conditions - the chances of success were not high but it would have been better than doing nothing.

However, Wei was too powerful and could not be defeated in a single blow, hence the expeditions had to be carried out in a careful manner with guaranteed advances rather than going with daring but risky strikes which could lead to disasters like the Battles of Xiaoting and Fancheng.

[47] Wei Yan's reasoning for his Ziwu Valley Plan was recorded in the Weilüe, which was then added as an annotation to his biography in the Sanguozhi, where Chen Shou recorded that Wei Yan received intelligence which led him to conclude that the defender of the strategic city of Chang'an, Xiahou Mao, was incompetent.

[48] Thus, Wei Yan reasoned, it would be easy for him to take 5,000 troops (and another 5,000 to carry supplies) across the Qin Mountains via the Ziwu Valley and into Chang'an.

[48] There, Wei Yan's force can wait for Zhuge Liang's main army to take the safer road out of Xie Valley (斜谷) and rendezvous in Chang'an.

[47] Yi Zhongtian, in his Analysis of the Three Kingdoms, commented that both proponents and opponents of Wei Yan's plan had strong reasons.

[47] However, Wei Yan's plan was also very risky, as neither Xiahou Mao's retreat nor the timely arrival of the main Shu force led by Zhuge Jiang could have been guaranteed.

[47] However, recent scholarship of Chinese history criticised the Weilue account, stating that Yu Huan had exaggerated the alleged conflict between Wei Yan and Zhuge Liang over the latter's rejection of the former's Ziwu Valley plan.

[50] Wen-Chin Wang of the Department of Chinese Language and Literature suspected that the Weilue account was biased since Yu Huan supported the state of Wei.

[52][6][53] A Wei Yan Shrine (魏延祠) is located in Baique Village, Sanquan Township, Zitong County, Sichuan.