The other reason is because most people only think of two things when they think of martial arts, Tae Kwon Do (and strangely they think they are thinking of karate), or Ninjitsu (but really they are thinking of Chris Farly). So I guess it is no surprise to you that there are children’s books about ninjas. Well it is a surprise to me!
Because I don’t mean children oriented like anime, I mean like easy reading. I have even found a site that will read it out loud to you, or your child. Now I’ve only listened to a short bit, but the story plot is like this, two kids have a magic tree house and it transports them to Japan where they run into some friendly ninja who help them find their lost friend. Some time down the road the ninja disembow someone and the kids spend the rest of their childhood in thearipy.
I didn’t listen to the end, so that last part may be slightly off the mark, but last time I checked the main things ninjas did was killing folks, and interestingly enough most parents try to keep their children away from that kind of thing, or so I am told.