During The Korean War, China Provided over 1,000,000 Soldiers To North Korean.
Ever heard of the Korean War?
A war between North Korea and South Korea.
Now, this is the reason why citizens of North Korea can only travel to no other Countries aside China and Russia. (Solely for Business purposes and not for Vacation).
Back in the 1940s during the Korea War in 1948, North Korea had only two Allies, which includes; China and Russia.
North Korean Side;
i. North Korea.
South Korea on the other hand had numerous allies consisting of 21 countries.
South Korean Side was LED by (among the 21 countries);
i. South Korea.
ii. United State of America.
iii. United Kingdom.
READ MORE about THE KOREAN WAR.