What is the name of this fighting movie from the 1980's?

It’s an American movie form the 80's, and it’s about a Father of two sons, I think they were Japanese, but their mother goes into the hospital, and towards the end of the movie she dies. But the father takes revenge, on the people that killed her. It has marital arts in it. The dad wears a black ninja outfit. And I remember there was a lot of those flying star daggers. There might be a final fight scene on a boat or yacht. The very last scene in the movie is at the mothers grave. I remember it from childhood, when it was on Betamax. Thanks for any help.