Japanese-Jewish common ancestry theory
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.
Source: Wikipedia — Japanese-Jewish common ancestry theory (CC BY-SA 4.0)