Sankin-kōtai

Sankin-kōtai is a long and difficult word that describes a tradition that happened in Japan a really long time ago. Back then, Japan was ruled by a really powerful person called a shogun. This shogun was very important and had lots of responsibilities, one of which was to make sure all the different parts of Japan were happy and didn't cause trouble.

To do this, the shogun came up with a plan called Sankin-kōtai. This plan said that all the important people who worked for the shogun had to travel back and forth from their home to where the shogun lived in the big city. This had to happen every two years and it was a really big deal.

Now to explain it like you're 5...Imagine you have a really important friend who lives far away and you want to make sure they are happy and don't have any problems. So, you come up with a plan where you will visit them every two years and bring them lots of nice things. But instead of just going yourself, you make sure that all your important friends come with you too. They have to make the long journey to your friend's house and they have to do it every two years. This way, your friend will know that you care about them and they will be happy.

It's kind of like a big sleepover with lots of friends but instead of playing games, they are all going to visit their really important friend who lives far away.