Summary: Mao came to power through ceding Chinese territory and licking the invaders' asses. Mao was the most despicable and ruthless traitor, a humiliation to the Chinese nation.

In terms of territorial area, China was the top defeated nation in World War II, due to Mao.

Mao's words“I hope to get full instruction from the top boss（Stalin)” will be his label in history.  

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Firstly, let's see the war situation in 1946: CCP's "God of War" Lin Biao with over 300,000 Russian stooges, was soundly defeated by 270,000 Chinese troops, asking George Marshall to issue a ceasefire order to survive; the Central Military Region suffered a complete defeat with Commander Li Xiannian, who became the head of state of PRC in 1983, fleeing in disguise; the top general Su Yu suffered seven defeats, losing the central part of Jiangsu Provence, and incurring losses twice that of the Nationalist army according to the self-reports of both sides; Marshall Chen Yi, the commander of CCP's strongest branch, was accused by his subordinates of "tactics are jokes"...

Unfortunately, the Chinese leader Chiang Kai-shek was too impatient. He promulgated a new Constitution at the end of 1946, with Article 119 negating Outer Mongolia's independence in the highest form. Stalin had determined to take Outer Mongolia and the US stood idly by. Truman's Asia policy has been declassified: "China is too poor and weak to justify a major commitment of resources. Rebuilding Japan is the key to controlling Asia"(see the screen-shot below). From 1947 onwards, Chiang Kai-shek's situation was even worse than Zelensky's today, who at least has the full support of the EU, especially the three major powers: Britain, France, and Germany.

According to figures reported by both sides: Stalin gave his stooges $900 million (from 1947-1949), while the United States gave China $225 million in "effective military aid" (see below). Furthermore, the book entitled "Секретные войны СССР: Самая полная энциклопедия" reveals that nearly a thousand Soviet soldiers "in the People's Liberation Army" died. The war's outcome: Soviet Russia legally gained two vast territories: the 64 villages east of the Heilongjiang River seized by Tsarist Russia and Tannu Tuva seized by Lenin, the "father" of the CCP.  "Civil war" does not change the borders between two countries; this is common sense. As Chinese Premier Yan Xishan and former Hubei Provincial Chairman Wan Yaohuang stated: this was Soviet invasion.

References

1, The 3600 square km territory ceded by the Russian stooge Mao.

2，Truman's Asian policy in 1947 

3, Aids received by both sides (self-reported).