Here's one of those shows popular in places that don't speak English.
Anime News Network tries to claim this show started in 2004. IT IS WRONG. It's been running since 1993. ANN does have 683 episode titles, which sounds a bit more like it.
THIS SHOW IS ABOUT NINJAS.
Rantaro, goes to ninja school to learn how to be a ninja with his two ninja friends Kirimaru and Shinbei. There are ninja teachers too. In particular Yamada and Doi. Yamada being the older ninja teacher who you see ninja disgusiing himself as a woman in the opening ninja clip.
By the way I have never seen this show and am simply precising information found here.
And guess what, this massively popular series is not available in English. Despite being ALL ABOUT NINJAS. It was dubbed into Spanish however. So there you go.