Man... This couldn't BE a more blatrant Dragonball ripoff if it tried. The art is very similar, the characters are very similar (a spiky-haired kid with superhuman strength & ninja skills, an older girl playing a nanny-like role, an irresponsible old geezer who's supposed to be teaching the kid, a villain who's a blatant piccolo ripoff).
At first Yaiba at least tried to be a little unique, with the plot revolving around competition for some ancient cursed swords instead of hunting for dragon balls. However, starting around chapter 55 they go on a scavenger hunt for magical spheres, one of which will summon a dragon. Sound familiar? ...Well, on top of that, there are 7 of these spheres (just like there are 7 dragon balls).
Despite such blatant plagiarism, this is a good & enjoyable series. The story is unique enough that it doesn't feel like you're watching Draginball reruns for the umpteenth time, but it does feel like you're reading the umpteenth sequel to the Dragonball franchise.