I learned very early on that Cruise had been a wrestler as a boy 
The director of Civil War Oscar-winner Glory, Gulf War drama Courage Under Fire and underrated terrorist thriller The Siege, Ed Zwick's latest is The Last Samurai. He tells you about Cruise, culture and "men to men" chemistry.
Why was Tom Cruise your first choice for this role?
He's an adventurous actor. He is a movie star but he also takes risks in parts. You think of him in Magnolia, Born On The Fourth of July, Interview With The Vampire. He's willing to go to these places and I think he constantly wants to push himself in every way, physically and emotionally.
And you pushed him physically in this, didn't you?
I did. I did. You know, I learned very early on that he'd been a wrestler as a boy and that's a very particular mentality. It shows a willingness to take punishment, so I knew I would be able to push him just as far as I needed.
Ken Watanabe gives a terrific performance as Katsumoto. How did you find him?
This is what I do for a living. I take pride in how I cast movies. I met a lot of actors, wonderful actors, but none of them inhabited the qualities I wanted this character to have. Suddenly Ken walked in and I knew in a heartbeat that he was the person to do the movie. He had this extraordinary humanity and spirituality and soulfulness that I couldn't deny.
How did you work on bringing their relationship to life on screen?
Chemistry is a hard thing to talk about. It's often talked about in terms of men and women, but it's about men and men too. I think the fact that they each have such power and confidence helped. It was almost as if I felt the character of Katsumoto had been lonely and the character of Algren had been alone and they finally found someone who understood the other and would understand what they were talking about. They found something kindred.
The attention to detail in this film is incredible. How did you ensure the Japan we are seeing is authentic?
The camera had been introduced into Japan about five years before this film is set and they went crazy for it. Everything was photographed: the streets, the costumes, the armour, every bit of it. So we were able to partake of this research and recreate it exactly because we had such extraordinary craftsmen and artists and designers. We were able to do what we saw had happened, that combination of the old and the new, the images of the rickshaw with the steam engine and the bowler hat next to the geisha. It was all there. All we had to do was reproduce it.
How was it being a director surrounded by a huge cast of Japanese actors, some of whom didn't speak any English?
You know, it's funny. There's great respect paid to a director in Japanese film. We were in a little town in New Zealand and there were often 500 men on the street. I would have to walk down the street to get my dry cleaning and grow accustomed to people actually bowing. I would bow back and it became quite common and understood. I quite missed it once I got back to Santa Monica and found nobody was bowing to me!
How do you sum up the heart of the film?
The kernel of the film is this idea that only when one can embrace the possibility of death, and understand that it is imminent to us all, can one truly and fully live. I think that's an idea I first conjured with when I encountered this culture at 17. I think it's something that's actually quite good to be reminded of. I also think for America and for the world, this understanding that cultures other than one's own are rich and complex and valuable is a very important one to have.
