Okay kiddo, have you ever seen those big sticks with a pointy end and two little weights on the sides that people use in movies to fight with on horses? That's called a bunchuk. It comes from a long time ago when people used it as a weapon in battle.
The pointy end is used to hit things and the two little weights on the sides make it easier to hold and swing around. It was also used in horseback riding because it can be used to guide the horse or control it.
People still like to play with bunchuks today, but now it's not for fighting anymore. It's just for fun! But remember, it's important to be safe when using it and not to hit anyone with it.