This movie is not well known under this title. But you may recognize it under its more common title, Ninja Wars.
Death of a Ninja is pretty remarkable. I think, given the proper presentation (original Japanese dialog, remastered video and sound), this would probably be an excellent movie. I mean, legitimately good. From what I understand it has won some awards in Japan. The version of this movie included in the Martial Arts 50 Movie Pack, however, has an absolutely hilarious dub and pretty atrocious (but watchable) video quality.
Especially when viewed with the English dubbed track (there is no other option on this disc), Death of a Ninja is pretty crazy. My understanding is that there is a difference in how we in the USA view ninjas and how people in Japan view them. We see ninjas as badass stealth assassins dressed in black. Japanese people (according to the movies I've seen from Japan) seem to see them as weird freaks with bizarre supernatural powers.
The plot is kind of complicated and I want to say you can ignore it and just watch the madness unfold, but then you lose out on a lot this movie offers if you ignore the plot.
A lecherous lord falls in love with the wife (Ukyodayu) of some other guy. Then a mysterious mystic (with the most hilarious dubbed voice I've ever had the pleasure to hear) appears literally out of nowhere to offer his services. The mystic will use his band of devil monks to create a love potion from the tears of a virgin who, in a glorious example of understatement mixed with some degree of self-censorship, must be "seduced" by the monks. It also helps if the virgin in question shares a bloodline with the woman. And wouldn't it be even better if she looked just like her too?
Luckily for all involved it just so happens that a girl ninja named Kagaribi looks exactly like Ukyodayu. The monks kidnap her because her ninja boyfriend, Jotaro, is totally incompetent. This won't be the first time that a woman gets kidnapped while under Jotaro's protection. Realizing what is to happen, Kagaribi uses her ninja powers to sever her own head with her bare hands but the monks will have none of that and they put her head on some other woman's body. You see they couldn't use the other woman because she is not a virgin. There was some reason why they did this but I had trouble following. Why not just put her head back on her body? Maybe they were afraid she would just sever her own head again.
So now it's up to Jotaro to get to the bottom of this. Can he defeat the devil monks? Can he save the woman he loves (or at least part of her)? Does it count to save only her head, or does he need to save both women for full points? And who's that really awesome ninja with the flowing mane of hair?
Death of a Ninja has plenty of the good stuff. It's violent like all ninja movies should be and there are plenty of good looking ladies in various states of disrobing. Kagaribi is awesome as she runs through the bamboo forest slashing down trees with her bare hands. Jotaro is useless until the very end, and even then his competence is debatable. Sonny Chiba is in it and even though he does nothing really other than scowl and look menacing he's at least one hundred times the man Jotaro is.
Earlier, I mentioned the difference between how we in the West see ninjas, and how they are seen in the mystical, inscrutable Orient. Honestly I like both styles of ninja. But I really like the ninjas in this movie. I think they even refer to the devil monks as ninjas in this one, and the devil monks have all sorts of cool powers. They're basically immortal. One of the guys can spit disgusting sticky acid stuff at you. Another guy has superhuman strength. And so on.
So if you like ninjas who are also weird freaky guys, I don't think you could do much better than Death of a Ninja.