What happened 20 August in China

In August 1940, the Red Army initiated the Hundred Regiments Campaign, in which 400,000 troops attacked the Japanese simultaneously in five provinces. It was a military success that resulted in the death of 20,000 Japanese, the disruption of railways and the loss of a coal mine.

Soviets invaded Japanese-held Manchuria.

On 20 August 1950, Premier Zhou Enlai informed the UN that "Korea is China's neighbor ... The Chinese people cannot but be concerned about a solution of the Korean question". Thus, through neutral-country diplomats, China warned that in safeguarding Chinese national security, they would intervene against the UN Command in Korea.