Japanese Koreaball was an annexed state of Japanese Empireball during the colonial period of Korean peninsula.
Back then, he was the largest overseas community of Empire of Japanball. The citizens of Korean Empireball were Japanese citizens with Japanese nationality. They official language was Japanese. While Empire of Japanball oppressed those who resisted, he also supported the economic development of Japanese Koreaball. He built modern cities, infrastructure, education etc that was lacking.
Force labor times
Independence and Division
Japanese Koreaball became independent in 1945. Then from 1950 till 1953 was the Korean War which divided the country. Primarily the military forces of Chinaball with a bit of help from Sovietball invaded Koreaball and created the communist puppet state of North Koreaball. USAball and UNball supported South Koreaball. This war ended in a stalemate.