What ninja movie am I thinking of?

Hi everyone. There is a film that I used to watch in High School and I am trying to remember the name of it. It's been nearly 20 years now since I've seen it so I will do my best to recollect it...

There is an Asian man whose family is killed (or something like that) and he retreats to an out of the way hut where he is trained by an old master for his eventual revenge. The old master makes him work around the hut. One thing I remember is he has to carry water buckets back and forth from the well to the hut daily.

At some point there is a funny seen involving a dog.. either he fights a dog or its his dog and other ninjas fight it. Don't quite remember....

Meanwhile, there is a second plot involving a white ninja (I always thought it was Franco Nero, but that's probably not right) But the white ninja was a white guy and I think he had a big mustache. There is a seen where the white ninja fights a bunch of other ninja's in a park. There is some lose reasoning that this ninja is looking for the Asian guy I think, but other than that it has nothing to do with the rest of the movie. It's almost as if these scenes with the white ninja were inserted into an older kung fu film for american audiences.

Finally the box cover art was awesome! There were ninjas, but most of all I remember a car driving though the box over explosions and people diving out of the way.

This ring a bell to anyone?