This map shows the proportion of non-Japanese residents by municipality. Back in 1995, most high proportion areas were concentrated in metropolitan areas like Tokyo, Osaka and Nagoya. But gradually, they started to include rural areas. The map includes foreign residents with visas valid longer than three months.
30 years ago, Koreans were the biggest nationality group in Japan. They have been decreasing however, with Chinese, Vietnamese, Filipino and Brazilian populations on the rise.
"Japan has opened the door to people from other countries to fill the lack of manpower," says Toshihiro Menju, Managing Director and Chief Program Officer of the Japan Center for International Exchange. "At first, the government expected people to stay only for the short or medium term. But actually the number of people choosing permanent residency has risen and they have had families."
The industry with the highest proportion of foreign workers in their 20s and 30s is agriculture, at 7.2%. It is followed by fisheries at 6.1% and manufacturing at 4.7%.
In Ibaraki Prefecture, north of Tokyo, almost one in every three young agricultural workers is from abroad. In Hiroshima Prefecture, it is one of every two young fisheries workers. These figures show the extent to which some industries have grown to rely on non-Japanese laborers.
The country's current immigration law grants working residence status only to highly skilled professionals, such as professors, doctors and lawyers. Other international workers mostly fall into two groups: technical trainees from developing countries sent under a Japanese government aid program; and students working part-time.
But in December 2018, the Diet passed a revised immigration law to ease these restrictions and allow more workers from abroad. It goes into effect in April.
The law introduces a new visa status, divided into two categories.
Under the first category, non-Japanese workers with "certain vocational skills" in specified fields will be allowed to stay in the country for up to five years. They are not allowed to bring their families. But under the second category, people with more advanced skills will be allowed to bring their families and will be permitted to live in the country indefinitely, "if conditions are met."
The government estimates an additional 345,000 workers in 14 industries, including construction and agriculture, will be accepted over the next five years.
But many issues need to be resolved if Japanese society is to exist harmoniously with this expected influx of workers from abroad.
Renan Eiji Teruya is a lawyer who is working to solve this problem. He is a third-generation Japanese-Brazilian and the son of a migrant worker. He is believed to be the first Brazilian to qualify as a lawyer in the country.
Teruya came to Japan at the age of eight with his mother, who was looking for work. He says she worked at a factory until late and would come home tired every day. Her experience made him want to become a lawyer to help people marginalized by Japanese society. His determination was hardened after his mother was nearly laid off in 2008 as a result of the Lehman Crisis.
Teruya says he wants to work to protect the rights of workers from other nations.
"We may face some issues that are similar to the ones faced by Japanese people, but there are more difficulties for foreigners," he says. "I think it's very problematic that some of the rights we have are different because some people cannot understand Japanese. I want to protect people from these harsh conditions."
Teruya has kept his Brazilian citizenship to maintain solidarity with other Brazilians living in the country. He says there is still some way to go before Japan is a welcoming society for incoming workers, despite the recent changes to labor law.
"I think some people would like to live here permanently after working here for several years. So I implore Japanese people not to see them as just a workforce. They pay taxes and do the same things you do."
"My cousin tells me there are now more nationalities in his primary school than there were during my childhood. I hope this results in younger generations growing up to be more accepting of other people."
The Japanese economy would be in dire straits without its growing workforce from abroad. But whether or not these people, who already play a crucial role in the future of the country, remain here long-term will depend on how accepting Japanese society becomes.