I read an article on an online publication a while back (I forget which) that claimed that Japan had a history of multiculturalism and the idea of a monolithic "Japanese" identity is just a myth. I know that in the modern era, only around 1% of Japan's population is immigrant, but I was wondering if there was any historical basis to this claim. To my knowledge, prior to the Meiji restoration, foreigners were only allowed into the port of Nagasaki, and that during the Imperialist era, Koreans and Taiwanese would be brought to Japan as labor, but I'm not aware of much regarding immigration to Japan in other timer periods.