It has taken 40 years for Kinji Fukasaku to break on to the international scene - and he had to murder 40 schoolchildren to do it. His latest film, Battle Royale, generated a national controversy in Japan with its violent premise, in which a class of schoolchildren are coerced into killing one another, until only one remains. A tacit indictment of Japan's competitive education system, its disaffected youth, and its faded martial pride, the film was opposed and almost banned by the government. Naturally, it then became a massive domestic hit.

Battle Royale has all the hallmarks of an angry young director out to make his name, but Fukasaku's name is already well-known in Japan. Aged 71, he is probably the most commercially successful director the country has ever produced. He began in the 1960s, shooting non-mainstream crime films, gradually making the genre his own, harnessing national frustration at Japan's postwar poverty, and sating audiences' desire for straightforward, contemporary action movies. His gangster output reached its peak in the 1970s, with the yakuza series Battles Without Honour, and Humanity, Japan's nearest equivalent to The Godfather.

These films have had a direct influence on modern directors like Takeshi Kitano (who plays the teacher in Battle Royale), Audition director Takashi Miike, and even Quentin Tarantino. Fukasaku's other work has covered just about every genre, from the war epic Tora! Tora! Tora! to The Black Lizard, a collaboration with Yukio Mishima, to Message From Space, a low-budget Japanese rip-off of Star Wars.

You're 71 years old. Why make a movie about teenagers?



Teenage violence has become a major social problem in Japan in recent years, but the phenomenon is confusing to adults. In the past there was still violence but there were always reasons behind it, like poverty. These days it is more difficult to understand, and so they don't know what to do about it. I have always been interested in the subject, but I am primarily a film-maker, and I didn't know how to make a film about it in a commercial way until I found this story.

Did you find it difficult to relate to modern teenagers?



How the children in the story reacted to violence reminded me of my own experiences during the second world war, when I was 15, the same age as the children in the film. So in a way I could identify with their situation. Children these days don't know anything about war. Even their parents didn't really experience it.

What was your experience of the war?



I was working in a weapons factory that was a regular target for enemy bombing. During the raids, even though we were friends working together, the only thing we would be thinking of was self-preservation. We would try to get behind each other or beneath dead bodies to avoid the bombs. When the raid was over, we didn't really blame each other, but it made me understand about the limits of friendship. I also had to clean up all the dead bodies after the bombings. I'm sure those experiences have influenced the way I look at violence.

There was quite a fuss with the Japanese authorities over the film. What really happened?



A politician raised the issue in the Japanese parliament. He said that Battle Royale could be harmful to children, and so they should intervene. Historically in Japan, the film industry has censored itself. But they said censorship should be controlled by outsiders. They were being foolish. We had many discussions but they didn't really go anywhere. By then, the film was already made. I travelled around Japan showing it to kids of 16 and 17, asking what they thought, and I felt that those youngsters were much more sensitive and sensible than those foolish adults who wasted so much time discussing the film. They didn't understand that their censorship was more harmful than the film itself. During the war, we weren't allowed to see any foreign films in Japan. Because I had had that experience of regret in my youth, I felt determined to fight against this censorship.



So what was the outcome?

The film was eventually rated R15, for people of 16 and over, which I was very much against. I was hoping it would be shown to people the same age as those in the film. Because it was forbidden, they wanted to watch it even more.



Another of your films people might have seen here is Tora! Tora! Tora! Have you seen the new Pearl Harbor?



I saw Pearl Harbor, but I think they cut certain sequences. I didn't think much of it. I couldn't really understand why anyone would want to make such a film; and its vision of the war seemed so unreal to me. My role in Tora! Tora! Tora! was more like a technical director for the aerial combat sequences. I was nothing to do with the screenplay. I had a lot of reservations about the project because I didn't feel the film portrayed the war that I had experienced. In the film, both the Japanese and American officers are portrayed as people who know what they are doing. If everybody had been so gentlemanly like that, the war would never have happened! It was what they did wrong that made them fight.



How was working with Beat Takeshi?



It was great fun, but it wasn't the first time. Ten years ago, I wanted him to star in a film but it never happened because our schedules didn't match. Takeshi was a busy TV personality, and the only schedule he could do was filming with me for a week then going back to TV for a week. I needed eight solid weeks with him. So I had to leave the project, and Kitano ended up directing it, and that became his first feature, Violent Cop. This was the first opportunity to work with him since then. I probably wouldn't have made Battle Royale if Takeshi couldn't have played that role.



You seem to have so much energy. What's your secret?



[Laughs] Battle Royale was the first film in 10 years I've felt passionate and enthusiastic about. So I didn't mind the physical or emotional difficulties. It's no secret. It's just better to do something you like than something you don't!

 Battle Royale is out next Friday.