The Japanese-Jewish common ancestry theory (日ユ同祖論, Nichiyu Dōsoron) is a fringe theory that appeared in the 17th century as a hypothesis which claimed the Japanese people were the main part of the Ten Lost Tribes of Israel. A later version portrayed them as descendants of a tribe of Central Asian Jewish converts to Nestorian Christianity. Some versions of the theory applied to the whole population, but others only claimed that a specific group within the Japanese people had descended from Jews.
Tudor Parfitt writes that "the spread of the fantasy of Israelite origin ... forms a consistent feature of the Western colonial enterprise", stating,
It is in fact in Japan that we can trace the most remarkable evolution in the Pacific of an imagined Judaic past. As elsewhere in the world, the theory that aspects of the country were to be explained via an Israelite model was introduced by Western agents.
Researcher and author Jon Entine emphasizes that DNA evidence excludes the possibility of...