Mao Zedong had a shaky relationship with Kim Il-Sung at times.

The tipping point came in 1956, when [Kim Il-Sung purged a bunch of pro-China factions in North Korea](https://en.wikipedia.org/wiki/August_faction_incident), prompting Mao Zedong to say that he might use the 400,000 Chinese troops still in North Korea to “help Kim Il-sung correct his mistakes.” 

On October 7, 1956, following a series of meetings with Kim Il-Sung that turned sour, the Chinese government made its decision: Mao Zedong ordered a military deployment of 500,000 combat troops to North Korea with the intention of overthrowing Kim Il-Sung,  a hundred more than he said he would use.

The invasion was launched in coordination with the Soviet Union, which deployed an additional 50,000 combat troops to North Korea to support Mao’s operation.

The invasion, codenamed “Red Harvest”, caught the North Koreans completely off guard, with North Korean forces scrambling to repel the invaders. 

The United States chose not to intervene, with the President at the time, Clovis Wade, saying, “Let the Communists war dogs destroy themselves.”

The joint Soviet-Chinese invasion force was met with stiff resistance not only from North Korean military forces, but from a fanatically hostile population.

According to diaries of various Soviet and Chinese military officers, the North Koreans created armed [civil defense](https://en.wikipedia.org/wiki/Civil_defense) units turned [militias](https://en.wikipedia.org/wiki/Militia), known as the Korean Volunteer Brigades (KVBs), who fought alongside the soldiers.

Many were armed with scavenged military weapons,  [molotov cocktails](https://en.wikipedia.org/wiki/Molotov_cocktail), [longbows](https://en.wikipedia.org/wiki/Yumi), swords, knives, bamboo or wooden spears, and even clubs and truncheons: they were expected to make do with what they had. According to an unknown North Korean citizen who was interviewed after the invasion, they were ordered to “kill one thousand invaders for every family that was slain by the enemy.”

Fighting was fiercest in Pyongyang, with Kim Il-Sung ordering the citizens to “die with honor”. In a move reminiscent of the Soviet Red Army, orders were given to execute anyone who chose to retreat instead. 

The fighting lasted until around November of 1957, during which Kim Il-Sung was killed during a military standoff with the Chinese and the Soviets. Kim Il-Sung’s son Kim Jong-Il was taken prisoner by the Soviets.

With Kim’s death, the capital city of Pyongyang fell under joint Soviet-Chinese occupation, similar to Berlin post-WW2.

The Kim regime in North Korea was over. 

Image credit:  
1. 14 Years of Flames  
2. Call of Duty: Black Ops  
3. Call of Duty: Black Ops Cold War

The Sino-North Korean War (Nova Aurora Universe)