So, in Japan a long time ago, there were lots of groups of people who lived together and helped each other out. These groups were called clans. A clan was like a big family where everyone helped each other and followed the same rules.
Clans had a leader who was like the boss of the family. They would make decisions and everyone would follow their instructions. The leader was often called the shogun.
Each clan had its own special symbol called a crest. The crest was like a picture that showed what the clan looked like. The crest would be on the clan's clothes, flags and even on their houses.
Clans were very important because they helped keep everyone safe. Sometimes there would be wars between different clans and if a clan was strong, they could protect their people from the other clans.
Some famous clans in Japan were the Takeda, the Tokugawa and the Oda. These clans were known for being very strong and powerful.
Today, there aren't really any clans in Japan anymore. But people still remember them and learn about their history. It's like how we learn about our family's history and traditions.