Ninja Hattori kun

What is it? I remember the artwork from my vague childhood memories (older than Doraemon memories even), and it seems to be both a manga and anime (some games too) but I just can't find it anywhere on the web. Is it one of those things that are so heavily patented that it's basically disappeared from existence in all respects?

Um-

Might you be referring to this? I don't remember it but I think I've heard of it before.

Yep, but I cannot find it anywhere online, and I don't have experience buying stuff from Japan, if they are even on sale there.