The Communist forces were initially in no position to resist Japan. It was left entirely to the Nationalists to defend Chinese territory. and they bore the brunt of the onslaught. The Communists entered the war with only 30.000 troops. In September 1937 they were reorganized into the Eighth Route Army. Shortly afterward. the New Fourth Army was established to operate in central China, comprising the remnants of troops left behind in the evacuation of the Jiangxi Soviet in 1934.
Mao was acutely aware of his party's strategic weakness, and he called for guerrilla warfare. the avoidance of direct confrontation with Japanese main forces, and the preservation and expansion of military resources. From 1937 to 1939, during the first two years of the war, Japanese forces stayed close to railway lines and depots. leaving the countryside unguarded. When they shifted their attention to securing their hold over broader areas, the CCP had already expanded into rural areas behind their lines. At this point some of Mao's commanders urged mobile warfare against the Japanese, arguing that guerilla warfare would have little impact. They called for closer cooperation with Nationalist forces in an effort to inflict larger losses on Japanese armies, and they received support from a number of party leaders. Mao, however, insisted on avoiding military confrontation and ordered the Eighth Route and New Fourth armies to disperse into small units and engage in recruitment, political work, and base area construction. Under this strategy, by design, there were to be very few clashes with Japanese troops, and even then only small ones. Japanese patrols or puppet Chinese security forces would be ambushed or raided for material and weapons. Collaborators were assassinated. rail lines torn up. mines laid on roads, telegraph poles cut down, and wire stolen.
The sole exception was 1940. With growing confidence due to their expanding control of the countryside. the CCP launched its only sustained offensive of the war. Mao authorized coordinated attacks by 104 regiments against rail lines. major roads, coal mines, and other infrastructure in Japanese hands. The Eighth Route Army lost 22.000 killed and wounded, while the Japanese lost an estimated 3,000 to 4,000. The Japanese sent large reinforcements on search and destroy operations and recovered all their lost territory, leveling villages that collaborated with the CCP, massacring human populations and livestock. and building blockhouses and strategic villages. The population in the Communist-controlled areas dropped from 44 to 25 million, and the Eighth Route Army shrank from 400,000 to 300,000. By 1942. 90 percent of the former Communist base areas on the North China Plain were under enemy control or were actively contested. Having provoked a fierce reaction, Mao reverted to his previous strategy and would never launch another major offensive against the Japanese.
There was a staggering imbalance in the burdens of combat. In January 1940, Zhou Enlai sent a report to Stalin, commenting on the favorable impact of the war against Japan. He stated that more than 1 million Chinese soldiers had been killed or wounded by August 1939, but only 30.000 from the Eighth Route Army and 1,000 from the New Fourth Army. Halfway into the war. the CCP had suffered only 3 percent of total Chinese military casualties. Despite their devastating losses. the Nationalists continually rebuilt their armed forces and persisted in their resistance against Japan in the years to come. The last major stand was their 1944 defense of Henan, Hunan, and Guangzi against a large Japanese offensive known as the lchigo Campaign. Nationalist forces suffered another 146,000 casualties. In the words of one analyst, Japan delivered a mortal blow to the Nationalist Chinese army from which she never had time to recover. By the end of the war it was "in an advanced stage of deterioration.."
In the wake of the Communist victory in 1949 and the CCP‘s subsequent decades of lavish self-praise as heroes of the anti-Japanese resistance, the Nationalist war effort has often been overlooked and denigrated. In the view of one of the most acute critics of the Nationalists’ failures, their military accomplishments were considerable: "[The Nationalist army] persisted for eight years in a war against an enemy force that was decidedly superior in organization, training. and equipment. . . . Completely frustrating Japanese expectations of a quick and decisive victory, it actively fought at Shanghai. at Nanking, and on the plains of North and Central China, incurring frightful losses... |and] mired the Japanese army in the vastness of the Chinese nation."‘ During the entire Chinese war, Japan suffered 483,708 dead and 1.9 million wounded, and Chinese forces suffered 1.3 million dead and 1.7 million wounded.
The Communists' contribution to the war effort was extremely modest. According to a December 1944 Soviet Comintern report, a total of more than 1 million Nationalist troops had been killed in battle, compared to 103,186 in the CCP's Eighth Route Army and another several thousand in the New Fourth Army. The Communists suffered only 10 percent of total Chinese military casualties. One author has called Mao's famous doctrine of people's war one of the "great myths" about the period: “people's war was hardly used in the conflict against the Japanese."
--- China Under Mao / Andrew G. Walder