Why are there so many Brazilians in Gunma County and Le Yi County?

I live in Mao Yi County. To be exact, there are many Brazilians in Daquan Town, Mao Yi County. From here, they radiate to the surrounding towns. In the past, Japan supported the founding of Brazil and exported many Japanese. Brazil has become the country with the largest number of Japanese immigrants. Since 1980s, Japan's economy has developed rapidly. Many Japanese descendants who went to Brazil returned to Japan to develop. First I went to Daquan Town, and then this place is just like Zhonghua Street abroad. This is a Brazilian town in Japan, where various Brazilian and South American cultures exchange and merge. We call them Japanese (they are only Japanese, not Japanese with Japanese nationality). It is normal to see a foreign face speaking Japanese and a Japanese face speaking Portuguese in the street. Our official languages are Japanese and Portuguese, and many signs are bilingual. When going to the government to do business, there is a Portuguese version of the form and a special Portuguese staff. You won't feel like you are in Japan here, as if you have come to a border town in South America. As Subaru's production plant is located in Ozu-CHO, many foreign workers enter here, mainly in South America. Foreigners in small towns account for one third of the total population.