> The reality of the war in China was far different. The Chinese army had not fought a serious battle with the Japanese since 1938. In the western sense it was really not an army at all, but a coalition of warlord bands scattered over twelve “war areas” which roughly corresponded to groupings of the old provinces of Imperial China. Each local warlord functioned as war area commander; in this capacity he exercised both civil and military control. Many of the warlord armies were ill-equipped and poorly trained. They seldom fought the Japanese, serving mainly to buttress the power of the war area commander instead. The core of divisions directly under the control of the generalissimo were better trained and equipped. But even they were undermanned and lacked artillery; in most cases they were commanded by officers chosen more for their loyalty to the generalissimo than for their military prowess.6

> “ ‘The general idea in the United States that China has fought Japan to a standstill and has had many glorious victories is a delusion,’ ” wrote a member of the American military mission to China. “ ‘Japan has generally been able to push forward any place she wanted to. She has stopped mainly because of the fact that a certain number of troops can safely hold only a certain number of miles of front. . . . The will to fight an aggressive action does not yet exist in the Chinese Army.’ ”7

> Corrupt, demoralized, inefficient, and oppressive, Chiang’s Kuomintang government was uninterested in “aggressive action.” It was interested in surviving the war against Japan with its armies intact, ready to deal with the generalissimo’s rivals among the warlords and his far more dangerous enemies, the Chinese Communist forces of Mao Tse-tung. A handful of Americans on the scene, like Ambassador Clarence Gauss, a dour New Englander with few illusions, attempted to enlighten Washington about the actual state of things, but had no discernable impact.8

And here's some discussion of Mao found in chapter 17:

> Yet the Communists profited from their mistakes. Under the leadership of Mao Tse-tung (who blamed the setbacks on his rivals, whom he then purged), the Communists concentrated on guerrilla warfare by small, widely dispersed units; their strategy emphasized the importance of building a solid base of support among the peasants by living among them and sharing their burdens and hardships.38 As Japanese units were gradually withdrawn from northern China to meet the Allied attacks in the Pacific, the Communists stepped up their guerrilla attacks. The Ichigo offensive brought them still more opportunities. By the fall of 1944 the Communists controlled large portions of four provinces. Their base areas were established in territory supposedly held by the Japanese but where the latter were too weak or too thinly spread to exercise any real control.

> At the start of the Ichigo attacks, Vice President Henry Wallace, on a special visit to Chungking, had urged that the Communists and Nationalists attempt to settle their differences in the face of the common danger and that an American military mission be allowed to visit the Communist base areas in the north.39 Chiang reluctantly agreed. The so-called “Dixie Mission,” composed of a small group of American soldiers and foreign service officers under Colonel David Barrett, arrived at Yenan in July 1944.

> The men of the Dixie Mission were favorably impressed by the Communist display of energy and aggressiveness. Communist leaders like Chu Teh, Chou En-lai, and Mao Tse-tung—with their informality, homely manner and apparent frankness—struck the Americans as a favorable contrast to the traditionalism and ritual formality of Koumintang leaders in Chungking.40 Discussions were held; plans were made by Wedemeyer’s headquarters and the OSS for military cooperation between the Americans and Communists, and for the Communist forces to receive lend-lease military supplies and American military instructors. (The OSS had, in fact, already begun some elementary small-arms and demolition training for Communist soldiers.41) All these projects came to nought, however, because of the strong opposition of General Hurley who, shortly after Stilwell’s recall, had replaced Clarence Gauss as U.S. ambassador to China. Hurley was in the midst of tortuous and ultimately futile negotiations to persuade the Chinese Communists to enter a coalition government under Chiang’s leadership; he wanted to use access to military assistance as a bargaining tool.42

I'd say that the comparison of the number of traditional battles fought that you're offering as evidence does not make sense given the nature of the two forces.

The fact of the matter is that the KMT by far did most of the fighting against Japan. This was directly admitted by Lü Zhengcao himself. It is also the mainstream view held by war historians. See [0] for a quick summary. You are the one putting forth a revisionist thesis.

The CCP's priorities were clarified in the orders Mao issued to the Eighth Route Army:

The Sino-Japanese war affords our party an excellent opportunity for expansion. Our fixed policy should be 70 percent expansion, 20 percent dealing with the Kuomintang, and 10 percent resisting Japan.

There are three stages in carrying out this fixed policy: the first is a compromising stage, in which sell-sacrifice should be made to show our outward obedience to the Central Government and adherence to the Three Principles of the People [nationality, democracy, and livelihood, as outlined by Dr. Sun Yat-sen], but in reality this will serve as camouflage for the existence and development of our party.

The second is a contending stage, in which two or three years should be spent in laying the foundation of our party’s political and military powers, and developing these until we can match and break the Kuomintang, and eliminate the influence of the litter north of the Yellow River. While waiting for an unusual turn of events, we should give the Japanese invader certain concessions.

The third is an offensive stage, in which our forces should penetrate deeply into Central China, sever the communications of the Central Government troops in various sectors, isolate and disperse them until we are ready for the counteroffensive and wrest the leadership from the hands of the Kuomintang.

From [1]:

By the CCP’s own accounts during the war, it barely played a role. Specifically, in January 1940 Zhou Enlai sent a secret report to Joseph Stalin which said that over a million Chinese had died fighting the Japanese through the summer of 1939. He further admitted that only 3 percent of those were CCP forces. In the same letter, Zhou pledged to continue to support Chiang and recognize “the key position of the Kuomintang in leading the organs of power and the army throughout the country.” In fact, in direct contradiction to Xi’s claims on Wednesday, Zhou acknowledged that Chiang and the KMT “united all the forces of the nation” in resisting Japan’s aggression.

From [5]:

Of course, wariness of fighting Japan was not the only reason Mao preferred guerrilla tactics to mobile warfare. Political calculations were at work as well. By focusing on the construction of base areas behind Japanese lines, Mao knew the CCP could build up its strength and improve its position vis-a‘-vis the KMT. Years later, one of Mao’s secretaries would recall a revealing remark Mao made to Lin Biao after the revolution: “Some comrades believed the less land Japan occupied, the better, only later was there unified recognition: allowing Japan to occupy more territory is the only way to love your country. Otherwise, it would have become a country that loved Chiang Kai-shek.” This comment, made to close associates in confidence, suggests that Mao saw Japan’s invasion as an opportunity to boost the CCP’s position in its continuing struggle with the KMT.

For example, after the Hundred Regiments Offensive [4], Mao purged Peng Dehuai for "wasting resources" fighting the Japanese rather than the KMT.

Even the CCP itself has been (slowly) starting to publicly acknowledge the historical truth [2][3].

[0] https://www.quora.com/Who-deserve-greater-credit-for-driving...?

[1] https://thediplomat.com/2014/09/the-ccp-didnt-fight-imperial...

[2] https://www.scmp.com/article/979073/historians-mainland-give...

[3] https://www.scmp.com/comment/insight-opinion/article/1591802...

[4] https://en.wikipedia.org/wiki/Hundred_Regiments_Offensive

[5] https://www.jstor.org/stable/20192272

Communist guerilla armies tend not to deploy regiments regularly. Mao discusses this in "On Guerilla Warfare". The NLF in Vietnam, the 26th of July movement in Cuba etc. we're not big on regiments.

Vietnamization and US withdrawal from Vietnam happened without much regiment deployment (other than the Tet offensive and a handful of other occasions). The guerilla tactics were fairly effective though.

"Guerrilla armies should fight like large, well funded armies" is a very old complaint that has been made. I'm sure the British and loyalists used it against George Washington.

> The only time it participated, it sent a mere 1,000 to 1,500 men, and then only as a security detachment on one of the flanks.There were 1,117 significant engagements on a scale smaller than a regular battle, but the CCP fought in only one. Of the approximately 40,000 skirmishes, just 200 were fought by the CCP, or 0.5 percent.”

and

> Specifically, in January 1940 Zhou Enlai sent a secret report to Joseph Stalin which said that over a million Chinese had died fighting the Japanese through the summer of 1939. He further admitted that only 3 percent of those were CCP forces.

Also, guerilla tactics are effective when the enemy is not willing to exterminate the enemy population. The Japanese absolutely were.

> I'm sure the British and loyalists used it against George Washington.

This is kinda overwrought. The US continental army did refrain from some continental-style line-up-and-shoot "tactics", but outside the south they engaged mostly in pitched battles. They didn't win by sniping redcoats here and there.

This is implausible, considering the Eighth Route Army (counted as the 18th Group Army by the Nationalists), which participated in e.g. the Battle of Taiyuan, started out with more than 30,000 soldiers and grew to several hundreds of thousands over the course of the war. https://en.wikipedia.org/wiki/Eighth_Route_Army

The only way you could come to the conclusion that the Communists only fought once is if you tried to assign all soldiers to either Nationalists or Communists, and discounted all Communist forces fighting as part of the United Front, which officially placed them under Nationalist command.