Why did Zhu Yuanzhang name "Korea"
It turns out that before they were named "Koryo", they were still Koryo dynasty. After Zhu Yuanzhang drove out the Yuan Dynasty and established the Ming Dynasty, the remnants of Mongolia moved northward, which was called the Northern Yuan Dynasty, while the Korean dynasty was still attached to the Northern Yuan Dynasty.
In the 20th year of Hongwu (1387), Zhu Yuanzhang sent generals Sheng Feng and Lan Yu to control Liaodong and Tieling, which happened to be the border between Yuan Dynasty and Korea. South Korean king Xin Qiji was young and ignorant, and sent an envoy to ask the Ming Dynasty to return Tieling. It is conceivable that Zhu Yuanzhang flatly rejected this matter. And this Xinyu is also soft-blooded, and actually ordered the mobilization of troops to conquer Liaodong.
Cao Minxiu and Li Chenggui were the commanders of the army. It happened that Li Chenggui had always opposed breaking with the Ming Dynasty. As a general, he knew that fighting the Ming Dynasty was like throwing eggs at a stone, but under the pressure of his superiors, he led the army to go out. So, shortly after he left, he led the army back to the headquarters, deposed Xinyu and established his own dynasty, known as the Li Dynasty.
In order to win the support of the Ming Dynasty, Li Chenggui submitted credentials to Zhu Yuanzhang and sent envoys to surrender to the Ming Dynasty. At the same time, he abolished the name of Korea and begged for a new name from the Ming Dynasty.
After careful consideration, Zhu Yuanzhang decided a new name for this dynasty-North Korea, and Zhu Yuanzhang also listed North Korea as one of the countries that had never been conquered. Since then, the name North Korea has continued to this day.
After the establishment of the suzerain-vassal relationship, all the kings of Korea sent envoys to the Ming Dynasty after they succeeded to the throne, and they were confirmed and titled by Ming Chengzu. The Ming dynasty took good care of North Korea and provided protection for it many times in times of crisis. The most famous is that in the 20th year of Wanli, that is, 1592, the Ming Dynasty helped North Korea resist the invasion of Japanese Toyotomi Hideyoshi and saved it from the disaster of national extinction.
In return, North Korea was loyal to the Ming Dynasty. Even after the demise of the Ming Dynasty, ostensibly under pressure, they secretly took in the adherents of the Ming Dynasty, calling the Qing Dynasty a "gourd country" and cultivating anti-Qing and regaining sight forces. The year number of Chongzhen, the last emperor of the Ming Dynasty, and the dress code of the Ming Dynasty have been used all the time.