Battle of Wuzhang Plains

The Battle of Wuzhang Plains was a stand-off between the contending states of Cao Wei and Shu Han in AD 234 during the Three Kingdoms period of Chinese history. The battle was the fifth and last of the northern expeditions led by Shu Han's chancellor, Zhuge Liang, who fell ill and died during the standoff.

Background
In the spring of 234, Zhuge Liang led 100,000 troops through Xiagu Pass (斜谷口) after three years of preparation since his last Northern Expedition. At the same time, Zhuge Liang sent an emissary to Shu Han's ally state, Eastern Wu, hoping that Wu would attack Cao Wei concurrently. In April, Shu forces reached the Wuzhang Plains near the Wei River and made camp there. The Cao Wei commander, Sima Yi, was well-prepared with a 200,000 strong army, which held a fortified position on the southern bank of the Wei River.

Initial clashes
Guo Huai suggested that Sima Yi form a position in the northern part of the Plains, since Zhuge Liang would likely strike there. Sima Yi agreed, and sent Guo Huai to set camp there. Shu forces attacked the Wei camp there while it was being built, but Guo Huai was able to hold them off.

Stalemate
Sima Yi would not engage the Shu forces, instead trying to make the enemy retreat through attrition. Zhuge Liang understood the problem, and implemented the tuntian system to sustain his troops.

The Shu army awaited an agreed offensive by Wu for the moment to strike. However, Sun Quan's armies in the Huai River region were defeated by forces led by the Wei emperor, Cao Rui, and succumbed to an endemic disease. Thus the stalemate remained in place and continued for hundreds of days. Shu forces tried to engage the Wei forces several times, but Sima Yi remained firmly in camp and refused to engage the enemy.

In an attempt to provoke Sima Yi to attack him, Zhuge Liang sent women's clothing to Sima, suggesting that Sima should be a woman since he did not dare to attack him. Sima Yi's subordinates were enraged by the insult, but Sima himself remained calm. To appease his men, Sima Yi asked Cao Rui for permission to engage the enemy. Cao Rui understood the situation and sent minister Xin Pi to persuade the Wei army to be patient.

Death of Zhuge Liang
In another attempt to force Sima Yi to go to battle, Zhuge Liang sent an emissary to urge Sima to fight him. However, Sima Yi refused to discuss military issues with the messenger, and instead inquired about Zhuge Liang's daily tasks. The emissary replied that Zhuge Liang had been personally overseeing all affairs in the army, ranging from strategic planning to his men's daily meals, and that Zhuge himself had not been eating and sleeping well. Sima Yi later told an aide that Zhuge Liang would not last long.



In August, Zhuge Liang fell ill due to exhaustion, and his condition worsened day by day. News reached the Shu emperor, Liu Shan, who sent minister Li Fu (李福) to ask Zhuge Liang about future plans for Shu. Zhuge Liang replied that Jiang Wan could succeed him, and Fei Yi could succeed Jiang. When Li Fu asked again about Fei Yi's successor, Zhuge Liang fell silent. Li Fu then returned to the capital Chengdu.

Zhuge Liang also gave instructions on how the Shu forces should withdraw back to Hanzhong: Yang Yi and Fei Yi would lead the army while Jiang Wei and Wei Yan would lead a force to defend the rear; if Wei Yan disobeyed orders, the army would proceed on without him. Zhuge Liang eventually died at the age of 54 in the early autumn of 234.

The Shu retreat
Following Zhuge Liang's death, the Shu forces quietly withdrew from their camps while not revealing news of Zhuge's death. Sima Yi was convinced by the locals that Zhuge Liang had died, so he gave chase to the retreating enemy. Jiang Wei then had Yang Yi turn around and pretend to strike. Seeing this, Sima Yi feared that Zhuge Liang had faked his death to lure him out, and immediately retreated. Common folklore tells of a double, or a wooden statue, disguised as Zhuge Liang, driving Sima Yi away in this incident. Another folktale tells that Jiang Wei dressed up as Zhuge Liang. In any case, word that Sima Yi fled from the already dead Zhuge Liang spread, spawning a popular saying, "A dead Zhuge scares away a living Zhongda (Sima Yi's style name)" (死諸葛嚇走活仲達). When Sima Yi heard of such ridicule, he laughingly responded, "I can predict the living, but not the dead."

News of Zhuge Liang's death were kept secret until the Shu army had reached the safety of the Baoye valley to return to Hanzhong. Sima Yi, fearful that the announcement was false and merely another opportunity for Zhuge Liang to demonstrate his talent for ambuscade, hesitated to pursue. Only after his inspection of the empty Shu encampment did he resolve that pursuit was appropriate. However, upon reaching Baoye, Sima Yi decided that they had insufficient supplies to support the advance, so he ordered a retreat back to the Wei River.

Conflict between Wei Yan and Yang Yi
Wei Yan, dismayed that the Shu forces are retreating "over the death of one man", gathered his men and rode ahead of the main army and razed the gallery road behind them to prevent the main army from returning home. Yang Yi, who held a personal grudge against Wei Yan, sent the emperor Liu Shan a letter accusing Wei Yan of treason; Wei Yan did likewise against Yang Yi. Liu Shan asked Dong Yun and Jiang Wan for their opinions, and both were suspicious of Wei Yan. Liu Shan then sent Jiang Wan to lead a force of imperial guards north to cope with the disorders.

Later, Yang Yi led the main army through the mountains despite the loss of the gallery roads and confronted Wei Yan's detachment at Southern Valley Pass (南谷口). There, Wei Yan sent troops to attack Yang Yi while Yang ordered Wang Ping to resist Wei Yan. Upon meeting, Wang Ping scolded Wei Yan, "His Excellency (Zhuge Liang) has died recently and his body has yet to turn cold; how dare you act this way!" Hearing this, Wei Yan's forces scattered, knowing their commander was in the wrong. Wei Yan, along with his sons and a few followers, fled to Hanzhong. Yang Yi sent Ma Dai to give chase, and soon Ma chopped off Wei Yan's head and sent it to Yang Yi. Yang Yi stepped on Wei Yan's head and issued orders for the extermination of Wei's clan.

Jiang Wan was about ten li away from the capital Chengdu when he heard news of Wei Yan's death, so he returned.

Long-term influences
After Zhuge Liang's death, Jiang Wan took his post, but Jiang was more interested in domestic affairs than military expansion. Thus the death of Zhuge Liang ended a huge strategic threat to Cao Wei and the Wei court soon began development of ambitious public works.

Sima Yi's success and subsequent rise in prominence paved the way for his grandson Sima Yan's founding of the Jin Dynasty, which would eventually bring an end to the Three Kingdoms period.

Modern references
The battle is featured as one of the final playable stages in Koei's video game series Dynasty Warriors. The earlier installments of the game changed the original account of the battle: certain characters such as Cao Cao and Liu Bei, who had historically died more than a decade before the battle, survived until then to participate in the battle. However, the most recent installment has made the battle more accurate than it was in the earlier installments.