Have you ever heard of the word "diaspora"? It means when a group of people from one place move to many different places and start new communities there.
The Japanese diaspora happened when many Japanese people left their home country of Japan and moved to other parts of the world, like the United States, Brazil, and Canada.
A long time ago, Japan was a very closed off country and didn't want people from other places to come in. But eventually, Japanese people wanted to explore the world and try new things, so they left Japan and went to different countries.
When they got to these new places, they started their own communities and brought their Japanese culture with them. They opened Japanese restaurants, celebrated Japanese holidays, and practiced traditional Japanese customs.
Even though the Japanese diaspora happened a long time ago, there are still many people all over the world who are proud of their Japanese heritage and keep their traditions alive.