When it was first established as a nation, Japan actively accepted people from abroad, absorbing the culture and technology of the Asian continent. Apparently, these newcomers numbered between one and three million people from the Yayoi period to the Asuka period. In fact, Japan is a nation that has developed through the proactive acceptance of immigrants and foreign technology. Waves of immigration include Spanish and Portuguese during the Azuchi and Momoyama period and Westerners during the Meiji period. The strategic acceptance of immigrants is a policy that should definitely be pursued to prevent Japan’s decline.