"The army and the people are one mind, who dare would oppose", as stated on the poster. China began to attack Khrushchev and Breznev through magazine cartoons and accusing them of cowardice over Cuba, incompetance, hatred of the chineese, and bretrayors of true revolutionary principles. This poster shows the people of China crushing Khruschev and Brezhnev
Then starting in 1959, the ideological tensions and mistrust began to boil over into border disputes, particularly on the China-Kazakhstan border and in north-eastern China on the Russia-Chinese border. These conflicts were pretty minor and usually involved standoffs and threats and occasionally small gunfights. Then, according to Vanbrandvijk in an article from 1974 stated that during the time 1963-1965, China even began to try to gain favor with their former enemy Japan by advocating that the USSR return the Kurile Islands to Japan, to which the USSR responded in a government newspaper editorial published on September 2, V-J Day, which "implicitly threatened China with the fate of the Japanese Empire, or in other words, military defeat, if it persisted in seeking territorial revision" . Vanbrandvijk then writes, "Khrushchev continued by accusing Mao of being of the same genre as Hitler and Tojo in the expansionist theater." Then even went Brezhnev took control from Khrushchev in 1964, there was no real change in regards to these border conflicts and the gaping hole between the USSR and Chinese leaders. Vanbrandvijk finishes with "Khrushchevism went on without Khrushchev."
The Soviet invasion of Czechoslovakia in August, 1968 further divided the two countries and justified many of the fears and mistrust China had towards the USSR. As the USSR adopted the Brezhnev doctrine which justified military intervention in any Warsaw Pact country if they deviated from Soviet socialism, China saw this as confirmation of Soviet imperialism and viewed the USSR as a global enemy to the true socialist cause. This incident also created more fear in China towrads posisble large scale military conflict between the USSR and China over their deviations of socialism.
All these ideological and national differences culminated on March 2nd, 1969, on Zhenbao Island, where Chinese and Soviet soldiers clashed leaving somewhere between 50 to 300 dead and hundreds more wounded. It is debated who started the fight, but many historians believe Chinese troops ambushed and started firing at Soviet troops which then became a month long conflict involving tens of thousands of arounds of artillery and tanks being deployed until both sides eventually backed off. This battle was the building crashing down moment of the relationship between these two communist countries.
Their ideological differences were so large and harbored so much mistrust that they created national issues and according to the CIA, almost a nuclear war. The head of the Soviet embassy in the U.S. , Davydov, asked a US official a question and this was how the declassified CIA paper told it, "Davydov asked point blank what the US would do if the Soviet Union attacked and destroyed China’s nuclear installations. I replied by asking him if he really meant this to be a serious question. He assured me that he was completely serious". This is the extent of the breach between these once allied, communist countries had become.