Nissen dōsoron

Nissen dōsoron (Japanese: 日鮮同祖論; lit. 'Theory on Japanese‑Korean Common Ancestry') is a theory that reinforces the idea that the Japanese people and the Korean people share a common ancestry. It was first introduced during the Japanese annexation of Korea in the early 20th century by Japanese historians from Tokyo Imperial University after adopting pre-existing theories conceived during the Meiji era. It mainly cites the Nihon Shoki, Kojiki, and Shinsen Shōjiroku to emphasize that the Japanese people descended from the Japanese deity, Amaterasu and the Korean people from Susanoo, her younger brother.