Isn't the title of the new film Ninja Assassin a tautology? To the average viewer, the word 'ninja' means 'assassin' by definition. In the 50 years since it spread from Eastern to Western popular culture, 'ninja' has become synonymous with sudden, silent death.
Possessed of lethal skills and dangerous magic, the ninja crept across the rooftops of feudal Japan; invisible and implacable, adept in poisons, disguises, and archaic weapons such as the 'shuriken' – those wickedly pointy throwing stars.
In the modern era, they have also been known to pursue moving cars on roller-skates, as seen in the unforgettable 1984 B-movie Ninja Thunderbolt (which was directed by Godfrey Ho, the Ed Wood of Hong Kong cinema). They are nothing if not adaptable.
A throwback to those earlier, cheaper efforts, Ninja Assassin is the latest and most expensive in a long tradition of stories about these so-called 'shadow warriors'. Produced by the Wachowski brothers, and influenced by the same Japanese cartoons and comic books that inspired their Matrix trilogy, it adds nothing to the ninja legend except new levels of computer-enhanced violence.
In this movie, bodies are not simply pierced by throwing stars, but shredded as if by machine-gun fire. Director James McTeigue has described it, without embarrassment, as "a cross between anime and a video game". The script was reportedly written in a record 53 hours. And like many before them, the makers do not seem to have done much historical research, or consulted any actual ninjas.
"What can I say?" sighs Paul Richardson, a British scholar and practitioner of various obscure and esoteric martial arts. "Hollywood isn't interested in the truth, or even in getting the story right, but fiction has surrounded the ninja for the past 500 years."
Richardson is as close to the real thing as anyone could expect to find in 21st-century Lincoln, where he teaches a regular class in ninjutsu – the way of the ninja. Actually, he explains, these terms are relatively recent collective terms for techniques once associated with various separate historical schools of combat, and people who used to go by many different names.
"'Shinobi', 'kusa', 'ozaru', 'suppa'... they were mostly samurai with certain abilities that made them of use to their lords." Their specialities apparently included sabotage and espionage, which were frequently employed during Japan's Sengoku, or 'warring states' period (between the 15th and 17th centuries), but not so much in the long and peaceful era that followed, when the covert operations of the past were exaggerated to supernatural heights by folk tales, wood-block prints, and kabuki plays.
"The stage," as Richardson puts it, "is the only place where the ninja ever wore black outfits and masks, with swords strapped to their backs." This is how they've been portrayed ever since – sometimes as heroes, more often as villains, and invariably prone to grandstanding tricks, such as burrowing under their enemies like evil moles, or swallowing whole attack-dogs in mid-leap. Myth and history have become so confused on this subject that few Japanese now believe that ninjas ever existed at all. Those who do tend to cite fictional examples like Sasake Sarutobi, a popular children's character – more cheeky than sneaky – created more than 150 years ago. "In Japan," says Richardson, "the ninja are a bit of a joke. It's a lot like Robin Hood – how many people know the facts behind that story? They only know the movie version."
In the West, meanwhile, the word itself is still most commonly associated with the Teenage Mutant Ninja Turtles, who were first conceived by two struggling New York comic book artists, Kevin Eastman and Peter Laird, as a satirical response to the sheer ubiquity of ninjas in the early 1980s. (Their franchise will soon be revived yet again with a new live-action movie.)
Martial artists now refer to this period as "the ninja boom", a time of low-rent video shop titles that followed in the wake of Bruce Lee, and drew a generation of young apprentices to at least one or two karate classes. "As a kid, I was fascinated by the idea of a hidden warrior who uses stealth to win," says Andrew Beattie, a professional film stuntman who is also one of the world's top-ranking instructors in Bujinkan Budo Taijutsu, a modern Japanese fighting system amalgamated from nine much older forms, including several schools of ninjutsu.
"But I also remember thinking there must be more to it. Those ninja movies sent me out looking for the truth."
Like Paul Richardson and many other Western pilgrims, Beattie found it in Noda City, just outside Tokyo, where he trained with veteran teacher Dr Masaaki Hatsumi. Having supposedly inherited his authority from the 33 Grandmasters who preceded him, Hatsumi co-founded the Bujinkan shortly after the Second World War, and effectively remains the Dalai Lama of ninjas.
To this day, Hatsumi claims that his ancestors were not assassins, but monkish fighting mystics whose relative absence from Japan's official records attests to their success in covering their tracks.
"The origins of this art," he has written, "are shrouded in centuries of mystery, concealment, and deliberate confusion of history."
To that end, silly movies like Ninja Assassin might continue to serve their purpose. Elderly but still adept, Hatsumi challenges his followers to doubt him if they like. Besides his demonstrable physical skills, he also holds a degree in theatre studies, and says that he sees "nothing wrong with the entertainment industry bending the lore of the ninja to fit the demands of the public". But it works both ways, of course. If nobody believes they exist, the ninja remain free to go about their business.
Ninja Assassin is released on 8 January