The Cambodia-Vietnam War was fought by Vietnam, which had won against France, the United States, and China at the time.
As soon as the war began, Vietnam entered the capital, Phnom Penh.
I wanted to take over Cambodia easily, but
Despite the support of the Cambodian people who opposed Pol Pot’s return to power,
They were trying to capture the remnants of the Khmer Rouge (Pol Pot’s political party) who had entered the jungle, but they themselves fell into a trap.
At that time, China, which had been keeping Vietnam in check politically, was supporting the Khmer Rouge from behind.
After barely maintaining a puppet regime and spending enormous war expenses, along with the stigma of being the Vietnam version of the Vietnam War,
Cambodia withdrew on the pretext that it could now become self-reliant.
In fact, this is a case of welcoming the occupation force out of antipathy toward the previous regime.
An example of guerrilla warfare and how eroding the distrust that exists despite it is.