The Korean War of 1950-53 is often labelled in Western historiography as the 'Forgotten War,' mainly due to the fact that it was largely subsumed in American historical consciousness by Vietnam. Probably so, but arguably what has been more 'forgotten' in most scholarly works on Korea, especially those written from a military analysis, have been the contributions of the Chinese, mainly in the form of the the People's Volunteer Army, whose numbers grew to about 3 million combatants and non-combatants by the end of the war.
This needs to be remedied, since it was such a remarkable achievement on the part of the Chinese. One should consider that the People's Republic of China was just a one year old, with Mao still struggling to establish his dominance over an impoverished country wrecked by years of brutal civil war and foreign invasion. The new Republic still hadn't managed to completely crush the Kuomintang, which still managed to menace mainland China from their new base in Taiwan. Their troops were composed mostly of peasant soldiers armed with rudimentary Soviet weaponary, and they had largely fought a guerrilla war against the KMT as opposed to the more conventional war which would be demanded of them in Korea. They had no navy and air force to speak of, depending almost entirely on Soviet material aid and expertise in helping establish them.
The fact that such a weak state was able to beat in open field one of the de facto superpowers of the Cold War era, pushing them back to the 38th Parallel, and crushing MacArthur's dream of stamping communism out of the Korean Peninsula, is quite an achievement. In this finely detailed military history of the Chinese contribution to the Korean War, Shu Guang Zhang attributes most of this to Mao's cultural and political understanding of war, mainly in his beliefs on how a much weaker state could beat a much more powerful one.
Mao's vision of war was, above all, political in nature. War was, in origin, inherently a class struggle, the 'highest form of struggle for resolving contradictions,' be they between nations, states, or political groups. As long as private property and inequality existed, then so would war. Maoist warfare was thus an interesting combination of both traditional Clausewitzian as well as Marxist-Leninist attitudes to war. However, Mao also believed heavily in ancient Chinese military maxims (namely that of Sun Tzu and the Romance of the Three Kingdoms) which emphasized how a much weaker military force could beat a much more powerful one, as well as the importance of mass public support in achieving victory. Mao believed that to win in war, one must understand its inherent character, believing that war was composed of units of opposites, such as advancing and retreating, fighting and resting, concentration and dispersion, etc. These units were intricately paired, but Mao believed that they would evolve as the war progressed, and it was he who managed to grasp these principles who would succeed in the long term.
Most importantly, Mao saw warfare as being composed of both objective and subjective conditions, Objective conditions were the material resources available to one's army, such as his population, his economic conditions, his weaponry on hand, the geographical conditions of the battlefield, etc. Subjective conditions, however, were more abstract, and included the strategic genius of the commander on the field, the morale and fighting spirit of one's troops, the public support back home, relations between the common soldiers and their officers etc. While acknowledging the importance of the objective conditions, Mao believed that in the ultimate pursuit of victory, they were secondary to one's subjective abilities.
This was ultimately, according to Shu Guang Zhang, the key point about Mao's military theories; namely his romanticized belief in the limitless potential of the human spirit and human creativity to overcome overwhelming material resources in warfare. Since war was entirely a human affair, thus only humans, or as Mao put it 'man's dynamic role,' which would ultimately determine its outcome. Going back to his notion of the 'units of opposites' and how dynamic and fluid it was, Mao believed the general with the greater wits and strategic genius would be able to manipulate his objective conditions in order to turn what was previous a previously weak position vis a vis the enemy into a strengthened one, moving from inferiority, to parity, to outright superiority. To summarize more succinctly, Mao argued: 'the stage of action of a military man is built upon objective material conditions, but on that stage he can direct the performance of many a drama, full of sound and color, power and grandeur.'
It was with this belief that Mao decided to plunge headfirst into the Korean War of 1950, fearing that the US-led UN drive toward the Yalu River would create an unacceptable American presence on China's northern border, which could threaten the entire revolution (American support for the KMT during and after the Civil War left a deep hostility towards the United States within the minds of most of the Communist leadership). Entering Korea on the 25th of October 1950, the Chinese People's Volunteer Army were able to catch the UN troops unaware. This was based on Mao's belief that war was largely based on surprise and deception, and indeed the PVA under Peng Duhai had taken concrete efforts to ensure their mobilization and entry into Korea was hidden from American intelligence. Since the PVA traveled largely on foot, they were able to utilize North Korea's largely mountainous and forested terrain to their advantage, avoiding the roads and therefore American aerial surveillance, before catching isolated UN positions by surprise, concentrating on surrounding and overwhelming them, while troops would be placed in their rears to both harass their supply lines as well as cut off their retreats. Attacks were often launched at night, to negate American airpower.
This strategy would work remarkably well in the early weeks of China's entry into the war, with the PVA able to push the UN into a humiliating retreat from the Yalu River to back over the 38th Parallel, at one point re-capturing Seoul. Delighted, Mao increasingly began to overestimate the abilities of his troops, ultimately demanding five large scale offensives with little break in between to drive the 'imperialists' out of the Korean Peninsula altogether. However, by the 'Fourth Offensive' in December 1950, the PVA were overstretched and exhausted, with supplies barely coming in, and the UN much better prepared to meet the Chinese on open field, learning to advance more in tandem and in coordination with each other, as well as learning how to position their troops as to make breakthroughs by the Chinese much more difficult and costly (most of the credit for this goes to the new commander in chief, Mathew B. Ridgeway).
The Fourth and Fifth Offensives were ultimately failures for the PVA, who suffered huge casualties and were forced to retreat back over the 38th Parallel. After that, there was largely a stalemate more or less along the 38th Parallel, as the Chinese switched from non-stop offensives to an 'active defense,' in which the Chinese would forgo sweeping, large scale offensives in favor of protracted piecemeal attacks along the entire front, focusing on the 'small scale annihilation' of relatively isolated enemy units in order to keep up pressure upon the UN as ceasefire talks were being held. The Chinese emphasized fighting 'seesaw battles' in which local PVA commanders were given more leeway to determine when it was appropriate to attack enemy units along the front, attacking when in strength, holding against the enemy counterattack, retreating back when the enemy response was too strong, before going back to the attack when appropriate. This method worked remarkably successfully, with casualties kept relatively low, and Chinese military commanders were urged to emulate them. Interestingly, one could consider this change of tactics as part of Mao's larger belief in the importance of understanding the 'units of opposites' in warfare, in this case the shift from the offensive to the defensive and back, and thus the larger overall shift from weakness to strength.
Shu Guang Zhang notes that the Chinese were often forced to improvise in order to survive against the technological superiority of the UN troops. Noting that throughout the entire duration of the war logistics and supply hampered the PVA, Zhang notes that the PVA were able to use remarkably creative tactics in order to ensure supplies reached the troops in the front while avoiding American airstrikes, such as using tunnels, ravines, galleys, and constructed coverts to quickly hide their trucks on the move, moving their trucks at specific times when air strikes were generally low, moving at night, placing decoy trucks to divert UN airstrikes, and placing look outs at high points to warn of impending air attacks. The Chinese were also able to utilize North Korea's extensive railway system, likewise innovating such as by moving numerous trains on one track at a time (often separated by short distances), as well as combining as many railcars as possible, to be both pushed and pulled by three or more locomotives. It was this innovation in supplying their troops which Shu considers one of many examples of how the Chinese were able to successfully manipulate the objective world using subjective conditions, in this case their imagination.
Another major aspect of Maoist thought concerning warfare was the morale of one's troops, which Peng Duhai and other commanders of the PVA took seriously. The average Chinese soldier was drilled about the political implications of an American victory over communism in Korea, urging soldiers to recount the sufferings they had experienced during the Civil War, and emphasize how the Americans, through their support for the KMT, had played a large role in it. Bravery in battle was rewarded by an intricate system of awards and medals, and made examples to be emulated by the other soldiers. The CCP urged local and regional governments back in China to provide extra care to the families of the troops stationed in Korea, as to put any worries the soldiers may have had at ease. Political mobilization of the public was a big factor in Maoist thought, and the Chinese government ensured that the public was supporting the troops as much as possible. Citizens were urged to donate small gifts to the troops abroad, as well as write them often touching letters to raise their spirits. More wealthier businessmen and industrialists in China's urban areas were urged to donate part of their wealth for the war. Ultimately, it was this emphasis on the morale of the troops and the political mobilization of the masses which formed part of Mao's belief in the 'subjective' conditions which would allow the Chinese to win.
Ultimately however, one shouldn't assume this book to be simply a romanticized recount of China's successes during the war. Shu makes a point to criticize Mao's often almost obsessive belief in the power of 'subjective conditions' in winning wars, noting the huge casualties the Chinese would encounter, and especially the major setbacks experienced during the Fourth and Fifth Offensive. Shu notes that all five offensives never achieved one of their main objectives, which was the utter destruction of the enemy, since the PVA, fighting largely on foot, could never effectively surround and destroy a motorized enemy which could quickly fall back. Expecting mass international sympathy, the Chinese were disappointed to note that even the Soviets were hesitant to outright support Mao's efforts in Korea, since Stalin feared an escalation to nuclear conflict with the West. The Chinese economy, already ruined by years of civil war, was further hampered by the war effort.
Shu also questions the effectiveness of Chinese efforts in mobilizing public support, noting that although the public may have been genuinely excited about the advance of their troops during the early months, that public support slowly dissipated over time as the war dragged on and casualties mounted. Efforts to raise the morale of the troops was also questionable, with Shu noting that the Chinese peasant soldiers could become very receptacle to American propaganda, which the PVA leadership took very seriously. Shu argues that even if the morale and discipline of the troops was high, how much this came down to the politicizing efforts of the Chinese military leadership is questionable, noting that they were raised in a culture where obedience to a superior came naturally to them anyway. Shu saves his major criticism of the overall concept of romanticizing the power of human spirit to overcome technology in war, noting that this belief had led many states to ruin (the most succinct example he gives is that of Saddam Hussein's Iraq during the First Gulf War.)
That being said, if there is one criticism to make of this book, is that Shu may be too harsh in his final analysis of the Chinese performance in Korea. It is still, without a doubt, a major achievement on the part of the China, at a time a weak, fragile state with an army comprised largely of peasant soldiers, to have pushed a UN force comprised largely of well trained and well equipped troops from the most powerful country in the world at the time back over the 38th Parallel. Like the Arabs after the Yom Kippur War, the Chinese had managed to regain their pride after years of foreign meddling and humiliation, and one would argue that Chinese success would ultimately validate Mao's statement made at the founding of the People's Republic, that the Chinese had finally 'stood up.'