Seiko-Kai Shito-Ryu Karate-Do Australia Ninja Birthday Parties Once you are a member of the Seiko- Kai Karate Centre, you can have a fun Ninja Birthday Party for your child. ts a change for your child to be the “Ninja Master” for the day, play Ninja games, win prizes and show your friends some of the skills you have learnt. Everyone who attends a Ninja Party gets a belt and headband to keep, with the Ninja Master who the party is for getting a special Ninja Master Belt, Headband and T Shirt.