Thank you.
You’ve proven part of present day N Korea was a foreign land occupied by Chinese forces.
All these events were before there ever was a Korea. Korea has never been part of China.
Suzerainty does not make the other state part of the suzerain state.
See this for some specifics on dynastic China
Historically, the Emperor of China saw himself as the centre of the entire civilized world, and diplomatic relations in East Asia were based on the theory that all rulers of the world derived their authority from the Emperor. The degree to which this authority existed in fact changed from dynasty to dynasty. However, even during periods when political power was distributed evenly across several political entities, Chinese political theory recognized only one emperor and asserted that his authority was paramount throughout the world. Diplomatic relations with the Chinese emperor were made on the theory of tributary states, although in practice tributary relations would often result in a form of trade under the theory that the emperor in his kindness would reward the tributary state with gifts of equal or greater value.
This system broke down in the 18th and 19th centuries in two ways. First during the 17th century, China was ruled by the ethnically Manchu Qing dynasty which ruled a multi-ethnic empire and justified their rule through different theories of rulership. While not contradicting traditional Han Chinese theories of the emperor as universal ruler, the Qing did begin to make a distinction between areas of the world which they ruled and areas which they did not. The system also broke down as China faced European powers whose theories of sovereignty were based on international law and relations between separate states.
https://en.wikipedia.org/wiki/Suzerainty
“All these events were before there ever was a Korea.”
There were -
- Koreans, these are an ancient, distinct people with a unique language and culture.
- The land now known as Korea, those mountains and valleys, towns and villages.
Both were at various times and in various parts, under Chinese Imperial rule, direct and indirect. That the various states and territories they were in were not called “Korea” is neither here nor there.
There was no “India” when the British conquered the place, they took Bengal, Madras, Hyderabad, etc. “India” was merely a geographical expression that covered much of Asia.