JAPAN invaded China in 1932. The CPC gave a call for putting an end to the civil war and resisting this aggression, which was well received by all sections of the people. The KMT ignored this call and continued its war against CPC stating that Japan’s occupation can be addressed later. Japan tried to mobilise all anti-communist forces in its favour and proposed ‘joint defence of Japan and China against communism’.

Influenced by Left sectarianism, CPC initially called people to unite and fight both the Japanese invasion and also Chiang Kai-shek. Very soon, CPC rectified its tactics and adopted a resolution stating that the basic forces of resistance will be workers, peasants, urban petty bourgeoisie and intellectuals, but it was ‘possible to form an anti-Japanese national united front with the national bourgeoisie as well’. It abandoned its anti-Chiang Kai-shek slogan and invited KMT for peace negotiations. CPC pledged that it would work together with the KMT, if the later guaranteed freedom of speech, assembly and association, released all political prisoners, organised a national conference involving all sections, improved people's livelihood and strengthened anti-Japanese resistance. KMT sat on CPC’s proposals and continued its offensive against the CPC.

Dissatisfied with Chiang Kai-shek's failure to stop the civil war and refusal for a united front against the Japanese, KMT's north-east army took him into custody in Xi'an. Though Chiang Kai-shek was forced to accept the terms of uniting with CPC to resist Japan, there was no visible change in KMT leadership’s attitude. They were still hoping to settle the issue ‘peacefully through diplomatic channels’. This was reflected in its call for ‘partial resistance’ against Japan’s invasion, in contrast to the CPC’s call for ‘total resistance’.

CPC decided that striving for a national united front under the leadership of the proletariat, it would wage an independent guerrilla warfare extensively in the enemy’s rear, open up battlefields and set up anti-Japanese base areas and win political and economic rights in the KMT areas through anti-Japanese mass movements. These tactics helped the CPC mobilise masses, unite patriots from all sections and gain support for the guerrilla struggle.

CPC decided not to join in the national government or any administrative council. “Such a participation would only obscure the distinctive features of the Communist Party, help prolong the KMT’s autocratic rule and impede, rather than further the effort to bring a unified democratic government into existence”. It would join such a government only after the ‘promulgation of an administrative order in accordance with the CPC’s Ten Point Programme for Resisting Japan and Saving the Nation’.

CPC’s persistence and popular pressure forced the KMT to recognise CPC’s legal status and proclaim the realisation of the Koumintang-Communist cooperation. In spite of this, the united front was never effectively ‘united’.

Meanwhile, certain Right capitulationist ideas rose within the CPC on the question of consolidating and broadening the anti-Japanese united front. They argued against CPC’s stress on independent initiative, democracy, people's livelihood and guerrilla warfare. They argued for ‘doing everything through the united front’, relinquishing the ‘leadership of the proletariat’ and relying on KMT for victory. Mao Zedong and others repudiated and combated these capitulationist ideas and clearly explained the need to uphold the principle of independence and initiative within the united front.

In 1937, Japan occupied Nanjing, the capital of KMT government and killed over 3,00,000 people in that city, in what is known as ‘Nanjing massacre’. The brutality of the Japanese army shook the entire country. This further weakened the fighting spirit of the KMT and by 1938, they lost large tracts of territory. Moved by the atrocities committed by the Japanese, many medical teams went in aid to China. Dr Norman Bethune from Canada and Dr Dwarkanath Kotnis from India led two such medical teams.

CPC persisted in its protracted and arduous guerrilla war against Japan and opened up the South China battlefield behind the enemy lines. People recognised CPC as the only force that can offer real challenge to Japan, resist their advance and safeguard the country. Youth rallied in huge numbers under the CPC banner and played an active role in the guerrilla struggle, increasing production in the base areas and strengthening the reserves of the People’s Liberation Army (PLA).

Showing great maturity and restraint, CPC reiterated its calls for unity in the fight against Japan. Encouraged by the British and the US, the KMT rejected all these appeals and continued its ambush of the CPC and the PLA. Japanese aggressors tried to utilise these divisions and launched an intense campaign to 'mop up' the liberated areas. CPC decided that it would continue to work for strengthening the united front, but KMT’s unreasonable attacks would be ‘repulsed without any compromise’. CPC was able to withstand and repel the attacks of the KMT as its stand of self-defence won people's support.

CPC decided to consolidate its bases in the north, strengthen its armed presence in the central regions and expand to the south in order to win the war of resistance. Suitable personnel were deputed to carry out these strategic tasks. As a result of these efforts, CPC’s membership grew from 40,000 to 8,00,000 by the end of 1940.

CPC concluded that ‘united front, armed struggle and Party building’ are the three chief magic weapons with which it can defeat the enemy and progress in the path of revolution. It issued an inner-party directive explaining the united front tactics: ‘it was neither all alliance and no struggle, nor all struggle and no alliance, but one that combined alliance and struggle’. Tactics should be worked making use of the contradictions to ‘win over the many, oppose the few and crush the enemies, one by one’. In order to correct itself from sectarian deviations and erroneous understandings of Marxism-Leninism, the CPC took up rectification campaign. The campaign was intended to fight subjectivism, sectarianism and stereotypes. Steeled by the rectification campaign, the army and people were able to frustrate the enemy, liberate and recover a large number of base areas.

On the other hand, KMT was able resist the Japanese only in a few battles and in most of them, they collapsed at the first encounter. Driven by its anti-communist hatred, KMT refused CPC’s repeated offers for the formation of a democratic coalition government even as late as, 1945. Politically corrupt KMT leadership failed to inspire their armies. An alarmed US strove hard to prop up the Chiang Kai-shek led KMT, but failed.

In 1945, Soviet Union entered China's north-east territories and launched a large scale offensive against the Japanese fascists, hastening their defeat. The PLA led by the CPC comprehensively defeated the Japanese forces, forcing them to surrender.

The war of resistance against Japan was a national liberation war in which China won complete victory for the first time in a century long struggle against foreign invaders. Over 2.1 crore (21 million) Chinese were killed or wounded, among whom were more than 6,00,000 fighters of the CPC. The CPC grew in strength, its liberated areas covered a territory of nearly ten lakh (1 million) square kilometers with a population of 10 crores (100 million). The main forces of the PLA exceeded 12 lakhs (1.2 million) and people's militia 26 lakhs (2.6 million). These laid the foundation for the victory of the new democratic revolution.

The Seventh National Congress of the CPC, called as a Congress of 'unity and victory', summed up the experience of its armed struggle and stated that the ‘three weapons’ responsible for its advance and with which to carry out the new democratic revolution are – integrating theory with practice, forging close ties with the masses and conducting self-criticism.

Dwelling on the situation after the victory over Japanese imperialism, CPC stated that without harbouring any illusions about the US and fully aware that Chiang Kai-shek would re-ignite another civil war, they should strive for peace and stability. The US once again tried to prop up Chiang Kai-shek, in order to checkmate CPC’s growth and helped him by providing logistical and material support. Buoyed by this, the KMT resumed its attack on the PLA and CPC in June 1946, violating the truce agreement it had signed six months earlier. CPC responded by calling for 'isolating the US and Chiang Kai-shek' and resistance to their efforts to ‘colonise China'. PLA employed its mobile warfare tactics and persisted against a superior enemy.

The Party issued a directive that in the second year of the war of liberation, the basic task was to launch a countrywide counter offensive. The Peoples' Armies led by the CPC achieved victories across China, marking a turning point in its history. CPC defined this period as a revolution against imperialism, feudalism and bureaucrat-capitalism that is waged under the leadership of the proletariat.

In the liberated areas, CPC adopted an 'outline land law' in 1947 to eliminate feudal exploitation and for the confiscation of land belonging to the landlords, for distribution among the landless. The general line on the implementation of land reforms stated that CPC has to rely on poor peasants, unite with the middle peasants and abolish feudal exploitation and develop agricultural production. These measures were supported by people at large and enabled the CPC secure victories over KMT.

By November 1948, CPC declared that its armies became superior in quality and numbers, indicating the imminent victory of the Chinese revolution and the realisation of peace. In February 1949, CPC reversed its slogan, ‘first the rural areas, then the cities’, to ‘first the cities, then the rural areas’. Nanjing, the headquarters of KMT fell in April 1949, signaling its comprehensive defeat.

On October 1, 1949 Mao Zedong proclaimed the formation of the Peoples' Republic of China (PRC). He declared it a ‘new democratic or a peoples' democratic State’, which is ‘led by the working class’, based on the ‘alliance of workers and peasants, uniting all democratic classes and nationalities’.

The founding of the PRC heralded the beginning of the transition of a semi-colonial, semi-feudal country into a socialist society.