because of the geography of the land, them being an island, this seperated them from having contact with korea and china because there was no form of communication . The isolated that Japan endured for over 200 years from Korea and China was set by the leaders of the time period.
Look at the map and you will find the reason is quite simple.
The neighboring countries of North Korea are South Korea, China, Russia, Japan, and Mongolia.
Japan fought against China and Korea.
It was separated by the Sea of Japan.
Japan is closer to Korea than China. The distance between Japan and Korea is about 210 kilometers (130 miles) across the Korea Strait, while the distance between Japan and China is around 1000 kilometers (620 miles) across the East China Sea.
China and North Korea have poorer economy compare to South Korea and Japan.
Japan is by China, the coasts of North Korea and South Korea and next to the sea of Japan.
Japan has no bordering countries since it is made of islands. The five closest countries to Japan are (in order) Russia, South Korea, North Korea, China, and Taiwan. North and South Korea, Russia and China.
The four countries closest to Japan are China, Russia, North Korea, and South Korea.
The Neighbors Of Japan Are RUSSIA AND CHINA
Japan, China, South Korea, North Korea, Vietnam, Laos.