Okay kiddo, so a long long time ago in Japan there were some people called Emishi. They were a group of people who lived in the northern part of the island, called Honshu. They were kinda like a tribe or a group of people.
The Emishi people were really good at fighting and they didn't like being told what to do, so sometimes they would fight against the other groups of people who lived in Japan. But sometimes they would also trade with these other groups of people.
Eventually, the Emishi people were kind of absorbed by the other groups of people around them and their culture and traditions started to change. But people still remember them today as an important part of Japan's history.