In December 2003, Tsugumi Oba and Takeshi Obata started a manga serial called Death Note for the Japanese manga magazine Weekly Shonen Jump. It ran for 108 chapters and finished in May 2006. That's when the storm really hit. The very next month, a live-action Death Note movie opened and went to the top of the Japanese box office, pushing The Da Vinci Code into second place. In October, this anime series I'm reviewing here started a nine-month run. A second live-action movie came out in November 2006 and then a third in February 2008, not to mention the two anime movies that are basically re-edited director's cuts of the TV series. The Hollywood remake is already in motion and apparently more than ten film companies were competing for the rights.

That's without getting into the novels and video games, by the way. Death Note is huge. It's been banned in China, been the cause of students being expelled from their schools in America and inspired copycat crimes around the world. So what is it?

Death Note has two brilliant ingredients: premise and story. The former is the obvious place to start. If you had the power to kill anyone you liked, with no possibility of failure and with no danger to yourself, would you do it? Is it right to kill people, if you're killing the right people? If you could kill every criminal, even those the law couldn't touch, would this be worth it to make the world safer for the innocent?

Light Yagami has such a power. The Death Note is a notebook which allows you to kill people simply by writing their names in it while keeping their face in mind, with the additional options of specifying time of death, how they die and what the victim will do immediately beforehand. If you don't specify or else if you ask for the impossible (e.g. the victim will teleport to a place of your choosing), then the victim will simply have a heart attack, forty seconds after you've finished writing. The rules for the Death Note are detailed, specific and, as far as I can tell, bulletproof. Tsugumi Oba's eliminated all loopholes. Its powers are terrifying but not limitless, instead being subject to certain restrictions which a clever enemy could take advantage of... and that's where the story comes in.

That's an astonishing premise. It's the kind of thought experiment that's likely to spark a discussion or three, if not more. Naturally this is mirrored by the fierce debate within the story itself, in which everyone has an opinion on the rights and wrongs of Kira's crusade against wrongdoers. (Obviously Light isn't doing it under his real name.) It never gets preachy, though. We simply see people with violently different viewpoints risking their lives on the line to further or hinder Light's goal of making a better world through mass murder and terror. What's specifically great about the story though is how intelligent it is. Light is a psychopath, but also the kind of genius you'd expect to become a world chess grandmaster or something. Meanwhile his confrontational approach, drawing attention to what he's doing and adopting the nom de guerre of "Kira", attracts the attention of the cleverest detective in the world.

That's the easy part, by the way. There are lots of so-called geniuses in fiction, with intelligence that's only depicted with "aha, you think you've been clever, but I've been cleverer!" speeches. Death Note though shows us the thought processes. We can see the chess game in operation, except that it's a game where the pieces really die. When it's really on form, which is most of the time, Death Note is unstoppable. It has several game-changing plot twists that had me gaping at my television, although unfortunately one of those is so brave that the story never fully recovers afterwards. The closing stretch of the series is still good, but it's not as intense as what had gone before and I'll confess that I got a little bored once or twice. That's the point where my wife had stopped reading the original manga, by the way.

You've got to respect the intellectual rigour with which it's been written, though. The only thing I can find that could be called a plot hole is the fact that shooting someone with a blank can still kill them if you're doing it at point-blank range. However I can't find any flaws at all in the Death Note rules and how the story's protagonists exploit them. If you think you've caught the story out, you haven't. Wait a few episodes and you'll find that there was a hidden reason you hadn't spotted.

It would be unforgivable to give away spoilers for the story, or even the cast, but I don't think it would hurt to say that Misa was funny. Secondly, I have a theory about the names. There's a generational thing going on, in which a character's position in the story is likely to have a rough correspondance with where they come in an alphabetical sequence. Kira (i.e. Killer) begins with K. (See also Kiyomi Takada and Kyosuke Higuchi.) Next come all the L-characters, who are all introduced early and/or fundamental to the story: L, Light, Raye Penber, Ryuuk and Rem. (There's no difference between R and L in Japanese, remember.) The next generation are represented by Misora, Misa, Mello, Mogi, Matsuda and Mikami. Finally note that the appropriately-named Jealous is a precursor to the whole thing, while one could correspondingly say that Near is far.

Don't pay any attention to the subtitles' transliterations, though. Apart from choosing to write Kira instead of Killer, they also spell Jealous as Gelus and go into amusing denial about the fact that the second opening theme song is shouting "sucker" and "fucker" loud and clear in English. What's even better is that I suspect they probably got away with it.

Visually it's great. It's a Madhouse show, which is always a good sign, and it's very faithful to the manga. I particularly liked the Shinigami and what little we see of their realm, which is bringing a Clive Barker sensibility to traditional Japanese folklore. "Shinigami" literally means "god of death", but there's lots of them and you can imagine them as being like Terry Pratchett's Death, but with fewer laughs.

I've also seen this described as a darker, more complicated version of Paranoia Agent, by the way. The difference is that Kira kills, whereas Shonen Bat just clubs you over the head.

There are all kinds of layers to this show. You've got cultists and pseudo-religion as Kira's crusade starts having an effect on the general population. You've got a protagonist who's capable of breathtaking evil, but who's nonetheless trying to change the world for the better. You've got a fierce ethical debate that's nonetheless sufficiently non-preachy that at least one critic has missed the point and called the show "morally repellent" with "a worldview that is both shallow and repulsively misanthropic". You've got a story that properly earns its 37-episode running time, which you don't always get with anime. There are too many 26 or even 13 episode shows that start treading water once you're past the opening stretch. I quite like what I've seen of the live-action movies so far, but obviously there you'll never get the depth of intelligence that's in this anime.

This isn't a cuddly show. The protagonist's a psychopath and we're following him on one of the worst murder sprees in history. What's fascinating is that we're being asked whether or not we want to cheer him on.