Kamakura-fu is a type of government system that used to exist in Japan a very long time ago, kind of like how you have a teacher in charge of your classroom. In this system, there was a very important person called the shogun, who was like the boss of all the other leaders. The shogun was in charge of the military and made all of the important decisions.
Under the shogun, there were other leaders called daimyos, who were like the heads of different regions or territories. They were responsible for making sure that their area was safe and that people were following the rules.
Kamakura-fu was first started in a place called Kamakura, which is why it's called that. It was a very important system that helped keep Japan running for a long time.
However, kamakura-fu doesn't exist anymore because things have changed a lot in Japan since then. Now, they have a different type of government system that works better for today's world.