An Analysis of Thedecline and Fall of the Shu-Han Kingdom During the Three Kingdoms Era

An Analysis of theDecline and Fall of the Shu-Han Kingdom During the Three Kingdoms era (220-280 AD)

Alex K Chen

Hstas 452

The Three Kingdoms period was a historical period in China that followed the collapse and general chaos of the Han Dynasty. It was marked by the survival of three independent kingdoms – founded by Liu Bei (161-223) of the Shu kingdom, who had control of the Sichaun Plains of Southwest China proper, Sun Quan (182-252) of the Wu Kingdom, who controlled southeast China south of the Yangtze River, and Cao Cao (165-220) of the Wei kingdom, who managed to control North China through defeating or absorbing many other warlords of the region (The Wei Kingdom would later become the Jin Kingdom after the Sima family usurped the throne from Cao Huan).Numerically speaking, Wei had the advantage over both kingdoms, as it had a much larger population and better-developed infrastructure. However, this did not make its conquest of the other two kingdoms inevitable, as the Wei Kingdom had launched numerous failed invasions of both kingdoms. Nonetheless, the Shu Kingdom was the first kingdom to fall. In this essay, I will argue that the Shu Kingdom was in a good position to indefinitely defend itself against the Wei Kingdom, but that several factors, combined with each other, were jointly sufficient to cause the kingdom’s downfall, even though none of them were sufficient by themselves. The first factor was the incompetence of the Shu-Han administration during the last 10 years of the regime (after 253 AD), which had happened after the emperor ignored the advice of others and put his court under the control of a corrupt eunuch named Huang Hao. The second factor consisted of the unsuccessful numerous northern expeditions (248 AD – 263 AD) that its Jiang Wei had launched against the Wei Kingdom. These northern expeditions, in turn, caused the Wei Kingdom to attack Shu first, even though it was previously focused on subjugating the Wu Kingdom first. And the third factor was that the Shu Kingdom failed to utilize its native talent, but rather, that it continued to rely on migrants for high office, even decades after its establishment.

Background of the Shu-Han Kingdom

The Shu-Han kingdom primarilyconsisted ofthe rich and fertile basin known as the Sichuan Basin, which was located in ancientYizhou Province (now Sichuan). It also held the territory immediately to the north of Sichuan – territory known as the Hanzhong valley, the source of the Han River and a region vital to the defense of Yizhou province, along with the western commanderies of Wudu and Yinping, which it captured in 229. It also nominally held some territory in the deep Southwest of China (territory that came from pacifying the local Nanman tribes). The Qinling Mountains effectively walled Shu off from the Wei kingdom to the north, providing easily defendable terrain for Shu (Jupp 2006). Finally, there was another mountain range that shielded Wu from Shu, effectively sealing off Shu from enemies in all directions (see Figure 1). Shu also had the advantage of being upstream of the other kingdoms, providing Shu with an additional defensive advantage (Sun 2009).

The kingdom effectively began when Liu Bei, an itinerant warlord with many loyal followers, managed to wrest control of Yizhou Province from its then-protector Liu Zhang(?-219) in 214 AD. Liu Bei effectively absorbed most of Liu Zhang’s followers. After Cao Pi (187-226) usurped the Han Dynasty in 220 AD, Liu Bei proclaimed himself as the next emperor of the Han Dynasty, supposedly to maintain the continuity of the dynasty. But Liu Bei died soon afterwards, leaving control of the kingdom to his son Liu Shan, (207-274) who would later turn out to be the last emperor of the kingdom.During the first 11 years of Liu Shan’s regime, Zhuge Liang presided over both the internal and external affairs of the kingdom. He launched five offensive expeditions against the Wei Kingdom, and while he did inflict numerous casualties on the Wei forces, he ultimately failed to reach his goal of capturing Chang’An. After Zhuge Liang’s death, Shu’s armies retreated, and Shu would not launch another expedition for 14 years.Meanwhile, the Wei Kingdom started to focus more on internal affairs and on subjugating local rebellions. In 248, however, Jiang Wei managed to convince the court that more northern expeditions were needed to finally crush the kingdom of Wei. Jiang Wei managed to launch 11 northern expeditions, and while he had achieved several successes, he was never able to capitalize on these successes because his armies always had to eventually retreat due to issues with his supply lines. Jiang Wei’s expeditions also resulted in several costly defeats, and they ultimately achieved little (while making the population tire of warfare). Most importantly, Jiang Wei’s northern expeditions had so exasperated Wei that it decided to eliminate Shu first. In 263, it sent out three armies to subdue Shu – armies under Deng Ai (197-265), Zhuge Xu, and Zhong Hui (207-264). While Jiang Wei managed to eliminate Zhuge Xu’s army through deception, and to also block Zhong Hui’s army at Saber Pass (to the point that Zhong Hui’s army came close to running out of supplies), Deng Ai decided to take an unexpected backterritory route through the mountains so that he could shock Shu-Han into surrendering.Just as Deng Ai was about to run out of supplies, he defeated the last army standing between him and the capital, and Liu Shan soon surrendered to him. Though Zhong Hui would soon rebel against Wei with Jiang Wei, his rebellion was crushed. This effectively ended the Shu-Han kingdom (Sima 1965).

Military Geography of Shu

Historically, due to these terrain advantages and the rich fertility and mild climate of the Sichuan basin, Southwest China has always been a uniquely natural and self-sustaining defensive fortress, without the natural disasters that the other kingdoms faced (Lewis 2009). In fact, this was the region of China where both the founders of the Qin and Han dynastiesstarted out, while all the other warlords were fighting each other. This was also the region where Gongsun Shu was able to maintain a sustained rebellion against the Later Han Dynasty (de Crespigny 2008). The Shu Kingdom had advantages that Qin Kingdom did not have in some ways, as the Sichuan basin of the Three Kingdoms period was much more developed than it was in the Qin Dynasty (who had to claim it by displacing the aboriginal Shu population).

Since the Shu army had controlled the Hanzhong region for several decades, their officers had superior local knowledge of the terrain. This local knowledge was especially useful for the mountainous terrain of Shu-Han, which is significantly more detailed than flat terrain, and where there are numerous natural places to set up ambushes along the narrow trails. These ambushes even managed to take down experienced generals like Zhang He (?-231), who was one of Cao Cao’s “Five Great Generals”, and who had 40 years of prior military experience.

There are three passages from Guanzhong (a term used to describe the west-central plains of China proper, including Chang’An) to Hanzhong - all of them valleys through the Qinling Mountains. These mountain passes, often known as the “Plank Roads of Shu”, were often so narrow that people could only move single-file through them (Jupp 2006). They were often adjacent to cliffs where soldiers could fall to their deaths, and were constructed of planks that could easily be burned (see Figures 3,4). The easternmost (and longest) passage was called the Ziwu valley, where the local rugged terrain had numerous spots that were perfect for ambushes. The westernmost passage had the Baoxie trail. Since the road condition was better on the Shu side than on the Wei side, the Shu Han kindgom could easily deploy their defensive forces and stop the attack before the Wei forces could get out of the valley.The central passage was named the Tangluo Trail, and it while it was the shortest passage among the three, it also had the poorest road conditions. Furthermore, it had the largest number of sections that did not have water supplies, which could cause a disaster if supply lines were blocked. These passages can be visualized in Figure 2.

The pathway from Hanzhong to Chengdu was also mountainous and non-smooth. Even after the Wei Kingdom managed to capture Hanzhong after Jiang Shu’s defection, it still struggled to get to Chengdu. In the end, it could not capture Shu-Han through the traditional passages, but rather, through an extremely risky backdoor passage.

When Cao Shuang used a force of 100,000 soldiers to invade Shu through the Tangluo Trail in 244,the Shu general Wang Ping managed to check his advance with only 30,000 soldiers. While Cao Shuang was waiting, so many of his horses died of thirst that he had to mobilize thousands of coolies to carry supplies for him – many who met the same fate as the horses. Once Cao Shuang was preparing to retreat, the Shu forces had already gathered reinforcements from the capital, who blocked the Wei retreat, causing over 100,000 of the Wei soldiers to die from thirst, hunger, and illness. Because Wei adopted the Tuntian system, where only soldiers would harvest crops for military purposes, the Wei Kingdom also had to withdraw 100,000 additional troops from its army to become farmers. This effectively dropped the Wei army size from 800,000 to 600,000, making it impossible for the Wei Kingdom to plan offensives against either Wu or Shu for at least 10 years (Sima 1965).

When the Wei forces invaded, they had to deal with ever-increasing supply lines. And these supply lines were often dangerous because they came through the narrow Plank Roads. These narrow passes made it easy for the Shu-Han forces to block enemy forces, and in fact, even during the final assault on Shu, Jiang Wei had managed to use his smaller army to indefinitely block Zhong Hui’s army. While Sun Tzu said that desperate troops, blocked from a path of retreat, can fight especially hard (Sun 2009), this observation does not apply as much when they are in a narrow passageway, in which case not all of the troops can be fighting at the same time. In fact, since most troops of the time were not professionally trained, most great campaigns of the time were only stalemated and were not decided by simple combat. Rather, victories were usually decided by issues of strategy, supply and morale. Most victories of the time came when the commander maintained his own force while the enemy’s force disintegrated (de Crespigny 1990, Ch. 8, pg 13).Since most victories of the era were not decided by simple combat, the numerical disproportionality between two kingdoms does not matter as much as it does for other wars.

Analysis of Shu

Despite several decades of warfare, Shu’s registered population had actually increased from 900,000 (as measured in the 221 census) to 1,082,000 by its demise in 263 (Chen 1959). This is a remarkable result, considering the extensive warfare that it had conducted against the Wei Kingdom. The Wu population was at 2,535,000 by the time of its demise, and the Wei population was at 4,432,881 at the time of its demise. While there were certainly stray populations that went uncounted in the census due to all the warfare, we can probably say that the uncounted portions of the population would probably not contribute to the military (or successes) of any one kingdom over another. The Wei population only had one million more people than the combined forces of Shu and Wu. Furthermore, the Wei population was much further spread out than the Shu population, so its population had to guard correspondingly more territory, especially against the dangerous tribes of the north. Finally, the Wei areas were also in a more disaster-prone region (speculation – cite this if possible) than the Shu areas, as the Wei areas were closer to the sea and Shu’s surrounding mountain ranges helped block out many of the storms that could otherwise have reached the area. If the Wei kingdom had to invade Shu, it could only do so by significantly outnumbering the Shu forces (or by waiting things out and waiting for a weak spot that the Shu could have provided).

The Military of Shu-Han Under Jiang Wei

Zhuge Liang had substantially fortified the passes to guard Hanzhong against Wei attacks. As a result, the region in 248 was technically more difficult to invade than the region in 214. However, in order to assume a more defensive posture, Jiang Wei dismantled the defensive corridors around these passes [Farmer 2007]. Previously, Liu Bei and Wang Ping adopted defensive strategies for each strategic position, where sufficient troops were deployed at each position to block enemies. This strategy was primarily responsible for the victory at the Battle of Xingshi (244), and was often sufficient to block enemies since only a small number of troops were required to hold each pass. However, Jiang Wei dismantled this system, and changed the system to one where the troops at each position would retreat to Hancheng and Yuecheng to prepare for a counteroffensive (Chen 1959). However, this strategy was fundamentally flawed. By the 263 campaign, the Wei armies still managed to take over the passes, by taking advantage of a dispute that arose between the two individuals responsible for guarding one of the passes - Fu Qian and Jiang Shu. Due to this dispute, Jiang Shu defected to Wei and opened up the gates, allowing the Wei forces to take the pass. Once they took the pass, they were now in a naturally defensible position, and it would be difficult for the Shu Kingdom to take it back (Sima 1965).

Jiang Wei was impatient to restore the Han, and often refused to listen to the advice of his generals who opposed his numerous expeditions. Shu-Han was simply not in a position to conduct extended military expeditions, and even when Jiang Wei had won victories, like his victory at the Battle of Didao (255), he could never follow them up due to problems with his supply lines. In fact, it has been argued (Farmer 2007) that he wanted to conduct his campaigns for the sake of personal glory, since he perceived that a victory over Wei could increase his prestige over that of Zhuge Liang. And during the last 10 years, Huang Hao did not oppose Jiang Wei’s campaigns, since these campaigns had effectively allowed him to dominate the Chengdu court. His numerous failures decreased the morale of the army, and the people of Shu-Han grew tired of war. Now that any stable Han administration had been gone for over half a century, few people had the nostalgia to return to a stable Han Dynasty.

Jiang Wei’s expeditions only provided perfect timing for the Wei Kingdom to finally decide to eliminate Shu first. While an expedition against Shu would have been considerably more difficult 10 years before its collapse, the corruption only exacerbated the communication and logistical problems of the Shu Kingdom.

Corruption of the Court

Meanwhile, after Fei Yi’s assassination in 253 AD, the court became increasingly dominated by the eunuch Huang Hao, who both Fei Yi and Dong Yun hated. Since Liu Shan seemed to care more about his harem than about external affairs, and also appeared to be fairly stupid (de Crespigny 2008), he easily believed the words of whoever he happened to trust the most, and Huang Hao happened to be that person after Fei Yi’s death. Huang Hao convinced Liu Shan to give out high positions to figures likeChen Zhi and Yan Yu, who achieved their positions not by basis of merit, but rather, by fawning on Huang Hao. Huang Hao also slandered other officials to keep them out of office. Meanwhile, potentially competent officials like Luo Xian andLiu Yong were dissuaded from entering court, and consequently did not participate in political or military activity. Huang Hao was a believer in witchcraft, and often found non-substantial explanations for his predictions – explanations that Liu Shan would nonetheless believe. For example, just as Wei was about to invade Shu in 263, he predicted that Wei would never invade Shu, a prediction that Liu Shan believed. Consequently, Liu Shan never sent the reinforcements that Jiang Wei had demanded until it was too late.

Xue Xu was a Wu envoy who observed Shu-Han’s decay from without. After he returned from his mission in 260, he noted that"All affairs of state are in the hands of a certain eunuch named Huang Hao, and all the courtiers look up to him as to a father. At court plain truth is never heard, and the country people look sallow and starved. The whole country appears on the verge of destruction. The birds on the roof do not know that the building is about to be burned." (Sima 1965)