Ninjas are fun. They're like the Freemasons, so wrapped in secrecy - and, indeed, defined by that secrecy - that someone making a movie can define them as being anything they want.Here, ninjas (or, as the subtitles would have it, "Nin Zaz") used to be several secret tribes of assassins, but through attrition and infighting, only one group remains. Now, these deadly Japanese killers are appearing in 1983 Hong Kong, targeting an unpleasant businessman.
The history lesson and glimpse at a ninja's training in the opening is hilarious. About two minutes in, a pair of female ninjas-in-training are placed in a pool of mud to spar, prompting a cry from the audience that this movie was the best thing ever. After that "promising" beginning, which also includes the female lead being introduced swordfighting in leather pants and a call girl being stabbed in the shower (by an icicle, so that the murder weapon would just melt), the exploitation quotient drops, but the martial arts content increases to compensate.
As is usual with these kung fu films, the story is just a loose structure on which to hang the martial arts sequences. Those are, fortunately, worth watching. The fighters are for the most part athletic (though one who is a solid mass of muscle moves pretty slowly). The final battle between a kendo teacher consulted by the police on several ninja-related deaths - whose parents and mentor were killed by ninjas - and the responsible ninja master who has been the unseen hand behind the killings (though, of course, on someone else's payroll) is suitably drawn-out to the point where it's almost exhausting to watch, but also has points where the absurdity of the ninjas hyper-ability is brought to bear - of course there are secret passages and hollow statues in this combination throne room/training area!
The characters are pretty far from complex, and aren't terribly well-acted - not that the hilariously bad subtitling does the cast any favors - but they are at least played broadly enough to be distinct from each other. Combine that with some amateurish-looking editing to make the ninjas look superhumanly fast, and the movie gains a certain amount of camp appeal.I'm not sure whether this film helped kick off the 1980s ninja craze or was meant to cash in on it, but it's an entertaining - if retroactively campy - example.