In the late 1950s and early 1960s, China and the Soviet Union looked like the perfect pairing, as they were two huge Communist powers challenging the Western world. However, by the end of the 1960s, the relationship between the powerhouses quickly began to deteriorate, turning from an alliance into competition for influence, and even to violence. What happened to cause this? How did the two nations go from allies to rivals? The answer lies in one of the most underreported stories of the Cold War. In 1949, when Mao Zedong took control of China and the Chinese Communist Party, he saw building a relationship with the Soviet Union as crucial…