This paper discusses the complex cultural and intellectual situation in the early phases of Japanese modernization by studying certain occult metahistorical tendencies that developed at the time, with special attention to interactions with similar tendencies from the West. In particular, I address a metahistorical discourse about the alleged relationships between Japan and the Jews, based on the concept of ultra-ancient history (chōkodaishi) that flourished from around 1930 to 1945 and is still partially influential today. As a window into occult metahistory, I will especially explore texts by Ogasawara Kōji (1903-1982). It appears that there existed a sort of “Dark Side” of Japanese modernization, deeply influenced by spiritualism, occultism, and theosophy imported from the West, which produced alternative discourses about Japanese identity and nationalism based on discredited Western ideas combined with creative interpretations of Japanese cultural texts.