In the Battle of Yiling, why did Lu Xun refuse Sun Quan's nephew Sun Huan's request for help?

In July 221, Liu Bei personally led a large army to attack Sun Quan, led by the generals Wu Ban, Feng Xi, and Zhang Nan, along the Yangtze River and the Wu Gorge, to retake Wu County (present-day north of Wushan, Chongqing), which was occupied by Eastern Wu, and directly attack the important town of Jiangling. Due to the popularity of the Romance of the Three Kingdoms, readers and friends believe that Liu Bei is moving out this time and mobilizing 700,000 troops. In fact, Liu Bei's troops on this expedition were only more than 40,000 people.

When Liu Bei set out from Zigui, Huang Quan, who was engaged in Zhizhong, suggested to Liu Bei: "The Wu people are fiercely fighting, while the water army is along the current, and it is easy to advance and retreat. The subject is invited to be a pioneer to taste the Kou, and His Majesty should be the back town. It should be said that Huang Quan's suggestion is relatively thoughtful. The Shu army went down the east, and it was easy to march and difficult to retreat. Huang Quan voluntarily led the army to test the falsehood of the Wu army, and let Liu Bei lead a large army to defend the rear, and once there was a loss, the entire army would not be destroyed. However, Liu Bei did not listen to Huang Quan's advice, but instead transferred him to Jiangbei and appointed him as the general of Zhenbei to guard against Cao Wei. Later, Liu Bei's army was defeated, and Huang Quan had no choice but to surrender to Cao Wei.

From Wuxia to Yiling (present-day east of Yichang City, Hubei), there are six or seven hundred miles of land, on both sides of the riverbank, high mountains into the clouds, the terrain situation is very complicated, if the war is lost, the enemy soldiers before and after, there is no way back, it is a taboo for soldiers. However, Liu Bei chose this terrain to fight against Eastern Wu. In February 222, Liu Bei's army advanced to Yiling, shezhou landed, on the south side of the riverbank, camped in a village, "more than seven hundred miles of camp", the army was very scattered, resulting in a serious weakening of combat effectiveness. In order to force the Eastern Wu commander Lu Xun to fight, Liu Bei sent troops to encircle Sun Huan, who was stationed in Yidao. Sun Huan was Sun Quan's nephew, so the Generals of the Wu Army demanded to send troops to rescue him, but Lu Xun knew that Sun Huan had a good army to lead the troops, was known as a soldier, and that Yidao City was strong and grainy, so Lu Xun refused the proposal to divide his troops to aid Yidao, avoiding dispersion and premature consumption of troops, so that he could concentrate his forces against Liu Bei. After the war, Sun Huan paid tribute to the general Jianwu and was a marquis of Fengdan. He was sent to build Hengjiang Dock and died young at the age of twenty-six. Liu Bei praised Sun Huan: "When I first came to the capital, (Sun) Huan was still a child, and now I am forced to be lonely and even this!" ”

Liu Bei personally led the main force stationed at Yiling Pavilion (present-day Yidu, Hubei, the ancient back of the north bank of the Yangtze River), and sent the general Wu Ban to challenge the Wu army, but Eastern Wu Luxun concentrated 50,000 superior troops and could not hold out. Liu Bei has been in the seventh and eighth months since he was established, and his soldiers have lost their vigor and are exhausted. In June of that year, Lu Xun took advantage of the midsummer to adopt the tactic of fire attack and launched an attack on the Shu army. The Eastern Wu generals each carried a torch and attacked with all their might, breaking the forward of the Shu army and beheading the Shu Han generals Feng Xi and Zhang Nan. Liu Bei withdrew to Ma'anshan (ma'anshan, in present-day Yichang, Hubei), Lu Xun pursued him, and the Shu army lost nearly 10,000 people. Liu Bei broke through the siege from Ma'anshan overnight, retreated to Zigui, and then retreated from Zigui to the White Emperor City (present-day Fengjie East, Chongqing). Lu Xun's column pursued, breaking more than forty battalions of the Shu army until WuXian County. In the Battle of Yiling, the Shu army was defeated, and history called the Shu army "boat equipment, water infantry and military resources, and was slightly exhausted for a while." The corpses drifted down the river." Liu Bei fell ill soon after retiring to the White Emperor City.

Less than three or four months after the end of the Battle of Yiling, the Wei lord Cao Pi divided his forces into two routes, attacking Eastern Wu's Fushu (濡濟) and Jiangling (江陵). Sun Quan sent envoys to contact Liu Bei, and Liu Bei sent Zong Wei to report for employment, and the fragile Wu-Shu alliance resumed.